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+{"metadata":{"id":"02cdff1c290aecf1fafa485de6b21849","source":"gardian_index","url":"https://cgspace.cgiar.org/rest/bitstreams/78d8dcdc-1cce-40a3-adac-20d211ef8216/retrieve"},"pageCount":161,"title":"United Nations Development Programme Ecologically Sustainable Cassava Plant Protection in South Ame rica and Africa: An Environmentally Sound Approach 1996 Annual report of Activities in South America Prepared by project personnelin Colombia and Brazil South American component of a global project involving","keywords":[],"chapters":[{"head":"","index":1,"paragraphs":[{"index":1,"size":111,"text":"provide additional biological control of cassava green mite, especially in dry regions. This pathogen naturally causes epizootics in Northeast Brazil, that periodically kili virtually all of the cassava green mites in a field in one or two weeks. Characterization of the biology and taxonomy of Neozygites c.f floridana strains using molecular genetic techniques have continued. The strain isolated fro_ m cassava green mite is highly specific to this genus, indicating that it would be safe to release in Africa. Preliminary experiments with RAPDs indicated that this would probably not be an efficient technology to use to identify Neozygites strains. Experiments with AFLP (amplified fragment length polymorphism) are showing more promising results."},{"index":2,"size":91,"text":"PROFISMA' s methodology for farmer participatory research was presented at liT A with the aim of facilitating the transfer and adaptation of these methods and experiences to the African countries with which ESCaPP is working. Although ESCaPP has been implementing its own strategy for training and farmer research (based on farmer field schools ), they became very interested in organizing a training event for Afiican scientists based on PROFISMA' s participatory research strategy. A proposal was jointly developed and submitted by liT A to IDRC-Canada seeking financial support for its implementation."},{"index":3,"size":66,"text":"Basic researcb at CIA T Acarology. In addition to the research mentioned above, the CIAT acarology program collected phytoseiid predatory mites in high altitude regions in Colombia, for possible release in high altitude zones in Afiica. Predatory mites (Typh/odroma/us tenuiscutus)from a dry region in coastal Ecuador, with climate similar to the target release zone in Northeast Brazil, were sent to CNPMF via quarantine at CNPMNEMBRAP A."},{"index":4,"size":71,"text":"The suitability of different prey and natural food sources for different phytoseiids was evaluated to leam more about the specificity of candidate species. The exploration database was analyzed to leam more about the geographic and climatic distribution of phytoseiid species to help select those most likely to succeed in various target release zones. The database was also analyzed to learn about the degree of host plant specificity of candidate phytoseiid mites."},{"index":5,"size":55,"text":"growing cycle for the period 1981-1995 by analysis of 60 field experiments. From the survey, 75 Phytophthora isolates were isolated, and these are currently being analyzed for biological and genetic differences. New in vitro and greenhouse methods of inoculation were developed to test varietal resistance, and 22 cultivars were inoculated with 4 Phytophthora spp. isolates."},{"index":6,"size":23,"text":"We developed a PCR method to characterize cassava root rot pathogens, which has been adopted by CNPMF IEMBRAP A _ scientists in Brazil."},{"index":7,"size":97,"text":"In vitro methods were developed to culture of Phytophthora species isolated from cassava, free ofbacterial contamination. We developed bioassays to study pathogen variability and to test cassava germplasm for resistance. Trichodenna spp., isolated from the rhizosphere of cassava plants were screened in vitro for antifungal activity against a range of fungal pathogens: Phytophthora drechs/eri, P. nicotianae, Dip/odia manihotis and Fusarium orysporum. Filtrates from líquid cultures of Trichodenna isolate 11 TSM-4 caused marked reduction in growth ofthe pathogen D. manihotis, and filtrates of 14PDA-4 were most effective in reducing the growth ofF. orysporum, suggesting promise for biological control."},{"index":8,"size":29,"text":"An effective thermotherapy method was developed to eliminate Phytophthora infections in cassava stem cuttings (planting material). This would permit stopping a major source of infection of newly-planted cassava fields."},{"index":9,"size":54,"text":"Fusarium so/ani and F oxysporum strains were obtained from 86 cassava samples obtained from different ecological zones in Colombia. Four methods of classification were tested for differentiation ofthe strains, including morphology, growth, pathogenicity and sitedirected PCR (rDNA). Screening of resistance has been conducted on 51 cassava cultivars by inoculating them with 28 Fusarium strains."},{"index":10,"size":60,"text":"In a survey of cassava growing areas in Colombia, 55 strains of Dip/odia manihotis were isolated, 8 of which were highly pathogenic to cassava plants. Three inoculation methods were used for pathogenicity studies, including stem injection, stem wounding and root cylinder inoculation. In a search for genetic resistance, 20 cassava cultivars have been inoculated with 40 strains of D. manihotis."},{"index":11,"size":90,"text":"Virology. An epidernic of geminivirus is causing extreme\\ y severe losses ( 50-100%) of cassava production in U ganda. W e discovered that the geminivirus causing the East African epidernic is distinct from either African cassava mosaic virus (ACMV) or East Africa cassava mosaic virus (EACMV), and it may actually be a hybrid of these viruses. The discovery of the true cause ofthe epidemic (i.e., not whiteflies) has made it possible to begin solving the problem by focusing on the evaluation and distribution of cassava varieties resistant to this newvrrus."},{"index":12,"size":76,"text":"In surveys conducted in Northeast Brazil, the disease caused by cassava vein mosaic virus (CVMV) was found to be very pr_ evalent, and often the majority ofplants in a field are infected with the virus. While there are indications that yield losses of 10-15% occur, further studies are needed to quantify losses due to CVMV. Such studies were not previously possible because of the difficulty of detection of the presence of the virus in symptom-less plants."},{"index":13,"size":74,"text":"A rapid method to detect the presence of CVMV was developed at CIA T using polymerase chain reaction (PCR) methods. This test is capable of detecting all isolates tested to date, even when visible symptoms are not present. This method has been transferred to laboratories in Brazil. Isolates of CVMV from six states in Brazil were characterized, and they differ significantly at the molecular level; however, this needs to be correlated with biological characteristics."},{"index":14,"size":105,"text":"Cassava frogskin virus has been expanding its geographic range in Latín America. It is now endemic in parts ofthe state ofBahia, Brazil. This probably occurred because ofthe major drought in 1992, that caused farmers to import cassava stem cuttings from neighboring states that border the Amazon region. Cassava frogskin disease (CFD) can cause the complete failure of a crop and is an important new pathogen that needs to be controlled. A microscopic analysis of the roots of CFD-affected cassava revealed very different structural features that are being evaluated as method to select CFD-tolerant cassava varieties, and the CIAT core germplasm collection is currently being screened."},{"index":15,"size":36,"text":"Whitefly transmitted geminiviruses are major problems in Africa and India. With the \"B\" biotype of Bemisia tabaci colonizing cassava in the Americas, increased efforts are being made to characterize the threat that geminiviruses pose to cassava."},{"index":16,"size":83,"text":"Agronomy. Long-term response of cassava to NPK (nitrogen, phosphorous, potassium) levels in acid infertile soils were measured at Santander de Quilichao, Colombia. After 13 consecutive cropping cycles without application ofNPK fertilizer, dry root yield was oniy about 4 t/ha. With application of 100 kglha each ófNPK, root yields were dramatically increased (about 10 tJha dry root). The largest observed response was for K, indicating that K is the most limiting nutrient in these soils, which have high organic matter content (ca. 7% )."},{"index":17,"size":22,"text":"To sustain reasonable productivity, K fertilizer must be applied annually since most K uptake (> 60%) is removed in the harvested roots."},{"index":18,"size":143,"text":"Long-term effects of surface mulch (grass), fertilizer and tillage on cassava productivity in poor sandy soil were measured at Pivijay, in northem Colombia. Dry root yield was significantly increased by the application of either mulch or NPK fertilizer at a moderate levels. Conventional tillage increased yield only in the presence ofNPK fertilization without mulch. The combination of surface mulch and no tillage gave the highest root yield with and without fertílizer. These findings indicate that consecutive cultivation of cassava in these poor soils would lead to very low yields unless appropriate measures are followed to maintain soil fertility. lnformation management. We scanned and formatted 11 major documents (2,800 pages) including recent CIAT Cassava Program annual reports, CIA T Working Documents, scientific meeting proceedings and Cassava Newsletters to be included in a CD-ROM being published by liT A and the University of Florida, Gainesville."}]},{"head":"Basic and applied research in Brazil","index":2,"paragraphs":[{"index":1,"size":107,"text":"Acarology. Five shipments ofthe phytoseiid predatory mite Typhlodromalus tenuiscutus, originally sent from CIA T, were made from the EMBRAP A/CNPMA quarantine facility to EMBRAP A/CNPMF (2, 150 individuals ). A colony was established and mass-rearing. Mass rearing of Neoseiulus californicus was carried out in a screenhouse on Tetranychus urticae on jack bean plants, enabling the production of33,500 individuals in a one month period. 10,800 T. tenuiscutus were released at 2 sites in Babia, and 34,020 N. californicus were released at 4 sites in Babia and Pernambuco. 28 specimens of N. californicus were recovered during monthly monitoring of the release si tes, suggesting that it may be establishing."},{"index":2,"size":52,"text":"In experiments using jack bean leaf discs that had previously been immersed in neem (Azadirachta indica) extract, we found that neem extract caused a decrease in survivorship of the two-spotted spider mite (Tetranychus urticae) but not its phytoseiid predator N ca/ifomicus. Studies on neem's effect on cassava green mite are under way."}]},{"head":"7","index":3,"paragraphs":[{"index":1,"size":79,"text":"CNPMF has 21 isolates of the mite pathogen Neozygites cf jloridana from several regions, in Brazil; however nine ofthem have lost their viability. Sorne isolates have been stored for up to 20 months as \"murnmies\" and still remain viable, whereas others have lost viability in as little as 6 months. V ariation in viability appears to be partly caused by the quality of the mummy and the amount of time that it spent in the field before being collected."},{"index":2,"size":38,"text":"Evaluation of different conditions for storing murnmies indicates that freezing ( -1 0°C) is generally better than 4°C or 25°C. Isolates from Cruz das Almas and Piritiba do not sporulate at relative humidity lower than 95% (at 24°C)."},{"index":3,"size":50,"text":"Neozygites isolates from T. urticae, collected in Cali, Colombia, and in Jaguariuna, State of Sao Paulo, Brazil, were pathogenic to both T. urticae and M tanajoa; on the other hand, the isolates from M tanajoa, collected in Brazil, were pathogenic only to M tanajoa, thus showing a very high specificity."},{"index":4,"size":92,"text":"The efficiency offield inoculation of Neozygites sp. to control CGM was studied by making ten inoculations (May 22 to June 24) using 40 mummified mites as source of inoculum. Although the first appearance of infected mi tes control and experimental fields occurred almost simultaneously, by August 2, the pathogen had spread all over the release field, whereas it was not found in the control field. The delay in initiation of an epizootic have may be due to the low mite population at the time (25 individualslleaf), low release rate orto climatic conditions."},{"index":5,"size":129,"text":"Entomology. A total of 111,610 parasitoids (Aenasius vexans, Apoanagyrus diversicomis and Acerophagus coccois) were produced, and 35,950 ofthem were released in six cassava fields in Babia and Pernambuco. A. diversicornis dispersed the most, reaching up to 304 km by April 1996. A. coccois dispersed more slowly, reaching 180 km from the releasing si~e by September/1995, while A. vexans has not dispersed from its release site as of November, 1996, despite the large number of releases. A negative correlation between number of parasitoids and mealybugs has been observed for both A. diversicornis and A. coccois in the State ofBahia, although A. coccois has a stronger effect on mealybug populations. Although mealybug populations fluctuate seasonally, the peaks are now about 20% the size of those observed befare establishment of the parasitoids."},{"index":6,"size":115,"text":"Plant pathology. Cassava witches' broom disease (CWBD), caused by a phytoplasm, is a very serious cassava problem in the \"Serrada Ibiapaba\", State ofCeará. An important achievement on the research of CWBD was the observation that elimination of infected planting material of susceptible varieties increased root yield. On farm trials to evaluate resistant germplasm were established in 60 rural communities, resulted in the selection of 2 improved clones that were preferred by 60% ofthe farmers to the local variety. Projected impact of adoption of these varieties, assuming adoption by 60% of the growers, implies replacement of about 3,000 ha of cassava and would represent 60,000 t increase in yield or about US$2.5 million increase in profits."},{"index":7,"size":113,"text":"A survey for the cassava root rot incidence was carried in three cassava growing regions ofthe State ofBahia. lsolations carried out under laboratory conditions showed that the pathogens involved in the cassava root rot development in the rural communities evaluated in the Bahía were Fusarium sp., Phytophthora sp. and Scyta/idium lignicola. A total of 179 varieties from the EMBRAPA/CNPMF Cassava Breeding Program were evaluated in on-farm experiments in Sergipe, Paraiba and Alagoas, permitting the selection of several varieties in each region that showed resistance to root rot. A farmer participatory trial showed that disease incidence is lower and root yield is higher when cassava is planted in ridges rather than on level ground."},{"index":8,"size":115,"text":"Field evaluation of 30 cassava hybrids, from the EMBRAP A/CNPMF Cassava Breeding Program, in the municipality of Umbauba, S tate of Sergipe, enabled the selection of five of them that were evaluated again in a on farm trial in a randomized block design, with three replicates. Eighteen cassava varietieslhybrids were evaluated for root rot incidence in a on farm trial carried out at the COP AL Quitéria, Municipality of Alagoa Grande, S tate of Paraiba, in a root rot naturally infested area. One hundred and seventy nine hybrids, from the EMBRAP A/CNPMF Cassava Breeding Program, were evaluated in on farm trials in the municipality ofVi~osa, State of Alagoas, where root rot incidence was relatively high."},{"index":9,"size":65,"text":"Due to erratic geographic and temporal incidence of cassava root rot, CNPMF decided to develop laboratory evaluation techniques to help complement field trials to identify cassava genotypes resistant to root rot pathogens. Several inoculation techniques were tested under laboratory and greenhouse conditions which generally showed that isoJates of Fusarium was not very virulent, but that isolates of P. drechs/eri and Scytalidium lignico/a expressed high virulence."},{"index":10,"size":42,"text":"Simultaneous inoculations of the antagonistic fungi Trichoderma polysporum, T. harzianum or T. pseudokoningii ~th the pathogen Phytophthora drechsleri were able to prevent it from producing normal sized lesions in sorne varieties of cassava, suggesting sorne possibilities for biological control of root rots."},{"index":11,"size":41,"text":"Virology. The main objective in 1996 was to determine root yield losses dueto the cassava vein mosaic virus (CVMV). Such an experiment requires a large amount ofvirus-free planting material, but the PCR diagnostic method was inadequate for testing this many plants."},{"index":12,"size":47,"text":"Consequently, the production of CVMV -specific antiserum became the main objective since this is easier to perform. Several modifications on the CVMV purification technique, such as viral separation through polyacrylamide gel electrophoresis; however, all have failed to eliminate the presence of host protein in the purified virus."},{"index":13,"size":17,"text":"We evaluated 20 host plants as possible alternate hosts ofCVMV, but the virus multiplied onJy in cassava."}]},{"head":"Agronomy. Experiments on duration of manual weed control at 2 sites in Bahía indicate","index":4,"paragraphs":[{"index":1,"size":81,"text":"that it has a significant effect on yield onJy during the first 30 to 60 d after planting. Other experiments combining various forms of weed control and intercropping showed that weeding within double rows of cassava and planting pigeon pea, cowpea or jack bean between the double rows produced higher yields than leaving weeds between the double rows. Although weeding between the double rows tended to increase yield (though not significantly), this was at a 30% higher cost due to labor."},{"index":2,"size":37,"text":"A field trial on the effect of intercropping with jack bean or cowpea between cassava double rows to reduce erosion showed no difference because of a drought in which no soil loss by surface run-off was recorded."},{"index":3,"size":76,"text":"On farm trials in Acarau showed that adding bagana (palm leaf waste) mulch at 180 m3 /ha, or more, increased cassava root yield (25.1 t/ha) in comparison to fields without bagana (8.1 tfha). Another trial in Russas showed no effect, possibly dueto rainfall that occurred during the period of initial growth of the crop. The course improved their skills, abilities and attitudes for using two participatory methods in the evaluation of technology testing trials with farmers."},{"index":4,"size":357,"text":"The first series of farmer participatory research experiments at 18 COP ALs in 4 states of Northeast Brazil were completed and evaluated and the second series was initiated. The various experiments included evaluation of regional varieties for yield and resistance to root rot, cassava green mite and whitefly, planting on ridges to control root rot, use of chemical fertilizers, organic compost or legume companion crops, to improve soil fertility, and row spacing. A few experiments failed because of drought or because of inadequate follow-up by the technicians. However, most experiments produced results that increased yields by 1 O to 67%. In several cases the EMBRAP A scientists leamed of local varieties that performed better than their \"improved\" varieties, thus providing them with new germplasm to incorporate in their breeding programs. They also began to leam more about the traits other than yield that farmers value, which will contri bu te significantly to the relevance of future crop breeding efforts. Socioeconomics. Intensive Diagnostic Survey was conducted in 18 cornmunities, involving 21 cassava growers in each cornmunity (9 COP AL members, 6 non-COP AL members, and 6 cassava growers from the neighborhood) in Northeast Brazil. Data were collected on land possession and usage, family composition, educationallevel, cassava production technology, and cornmercialization of cassava. Data were also collected on incidence of pests and diseases and the methods being u sed to control them. Over 50% of cassava growers had less than 5 ha. surveyed do not own the land they cultivate. About 29.9% ofthe land used as pasture, 29.9% is left under fallow, and 13.2% is natural vegetation, all of them general! y used for grazing. About 89% ofthe daughters, 81% ofthe sons, and 57% ofthe parents do not have any school education. The head ofthe family is predominantly aman older than 18 years; 52.5% of them are 50 years old or less. Approximately one third of the family members does not work in the rural cornmunity: they are either school age children or young people whose activities are other than rural labor. About 29%, besides working on their land, also sell their labor in order to make extra money."},{"index":5,"size":46,"text":"Most ofthe growers (64%) prepare the soil for planting only by manual hoeing. About 73% ofthe cassava growers use their own cassava stakes to start a new planting, and only 42% of them reported carrying out any kind of selection of stake quality prior to harvesting."},{"index":6,"size":76,"text":"Only 64% said that the stake must be 1 O to 20 cm long have a diameter greater than 2 cm. Farmers considered leafcutting ants, root rots, homworm, cassava green mite, and whiteflies to be the most important pest and disease problems. Although witches' broom disease is fairly uncommon, it can cause extremely high yield losses (72%). Farmers used pesticides only to controlleafcutting ants, homworms and anthracnose, and lime or ash to help control root rots."},{"index":7,"size":46,"text":"The majority of the cassava production in the Northeast (77%) is sold as cassava tlour, .. 19% as fresh roots, l . 6% as animal feed, and only O. 7% as dry chips. About a third of the aerial plant parts are used for feeding animals."}]},{"head":"Project management","index":5,"paragraphs":[{"index":1,"size":239,"text":"Due to anticipated reduction of funding in 1997, the CIAT coordinator in Brazil decided to eliminate bis own position, as well as those of sorne junior statf in Brazil and at CIAT. Project coordination by CIAT during 1997 was devolved to other staffin Cali, Colombia. 12 A concept note entitled, \"Ecologically Sustainable Cassava Production Systems for Latin America\" was prepared by CIAT and sent to 25 donors in May with the goal offinding additional donors to support a subsequent project based on the successes of this project. A second concept note entitled, \"Ecologically Sustainable Cassava Plant Protection: A Global Strategy\" was written jointly by CIAT and liT A in July to unifY the Latín American and By far the most impressive accomplishment of the project to date is the establishment, spread and measured impact of Typhlodromalus aripo (a phytoseiid mi te predator of cassava green rnite [CGM]). Field trials have demonstrated reductions in CGM numbers ofup to 90%, and econornic impact regarding increased root yields of 30%, corresponding to profits of about US$ 60/ha per crop cycle. Area-wide benefit will undoubtedly be a significant (in the $10-100 rnillions per year), and benefit will continue year-after-year because ofthe selfsustaining nature of classical biological control. This will no doubt represent an extremely high retum on the initial donor investment, causing widespread impact on food production and econornic development in the lowland humid tropics of sub-Saharan Africa, with no adverse environmental impact."},{"index":2,"size":4,"text":"Major accomplishments of PROFISMA  "}]},{"head":"Visiting UNDP Headquarters","index":6,"paragraphs":[{"index":1,"size":32,"text":"The EMBRAP A/CNPMF Director of Research and Development, together with CIA T' s representatives, visited UNDP headquarters in order to discuss financia! support for the extension of the Project, starting in 1997."},{"index":2,"size":7,"text":"Arrangements for continuing PROFISMA activities during 1997"},{"index":3,"size":82,"text":"The project coordinator for PROFISMA is terminating bis position at the end of December 1996. This will substantially reduce project costs, helping us to retain other essential technical personnel during 1997. However, it will reduce the amount of supervision and coordination of activities between CIA T and CNPMF. It al so greatly decreases our capability to communicate wíth donors in the search for funding to support subsequent projects that will extend and solidify the progress that this project has obtained to date."},{"index":4,"size":49,"text":"A money-saving policy was implemented at EMBRAP A/CNPMF during 1996, based on two main actions: 1) EMBRAPA's financia! aid for operational costs, and administrative and scientific personnel; and 2) rationally reducing project personnel. Two field workers, the project secretary, one lab technician, the Virologist and the Environmentalist were dismissed."},{"index":5,"size":13,"text":"In addition, EMBRAPA did not charge PROFISMA overhead costs to UNDP during 1996."},{"index":6,"size":59,"text":"Such procedures made it possible to maintain PROFISMA activities during 1997, though at reduced levels. The operational budget for 1997 will be provided by EMBRAP A, which is also expected to supply additional personnel when necessary. PROFISMA personnel will be paid using carryover from the 1926 budget plus bridging money provided by UNDP, as previously discussed with UNDP representatives."},{"index":7,"size":18,"text":"3 TRAINING AND PARTICIPATORY RESEARCH PROFISMA's strategy for this activity was defined as a combination oftwo methods: a)"},{"index":8,"size":46,"text":"agronomic evaluation (the one commonly realized by researchers to determine yields, dry matter content, and other parameters) and b) technology evaluation by farmers (evaluation oftechnology trials using complementary techniques). The technique utilized was the so called Preference Ranking. For each evaluation the procedure was as follows:"},{"index":9,"size":17,"text":"• The COP AL coordinated the activities and requested assistance from other interested farmers in the community."},{"index":10,"size":16,"text":"• A short meeting was held to discuss the activities, the organization and to assign responsibilities."},{"index":11,"size":14,"text":"• Farmers participated in the harvest of each treatment, each replication and each block."},{"index":12,"size":86,"text":"• Cassava roots and aerial plant parts harvested for each replication and each experimental block were laid on the floor grouped by treatments, and farmers were asked to rate them (the best, the second, the last, etc.) using small pieces ofpaper with printed numbers. Each farmer represented one vote, and he voted on all the treatments. During their ranking of the different treatments, farmers were allowed to discuss among themselves about the criteria they were using. Technicians were asked to avoid any participation in this step."},{"index":13,"size":92,"text":"• After all the treatments have been ranked by the farmers, a final counting was made assigning points to each classification. For example, in an experiment with four treatments, the best treatment was assigned number 1 and was worth four points; the second, was assigned number two and was worth three points; the third, number three and was worth two points and the last one, was assigned number fourth and was worth one point. By adding the points assigned to each treatment, a final Preference Ranking, according to farmers criteria was obtained."},{"index":14,"size":16,"text":"• Farmers were invited to comment on this ranking (especially regarding the criteria they u sed)."},{"index":15,"size":48,"text":"• Agronomic evaluation was conducted jointly by technicians and farmers. Each treatment was weighed (cassava roots and aerial plant parts). For dry matter determinations a sample was taken for each treatment, and the dry cassava content was determined in front of the farmers using the hydrostatic balance method."},{"index":16,"size":40,"text":"• A rapid analysis of the results was made on the spot and was u sed to stimulate the final discussion with the farmers. Raw, semi-processed data ofthe results ofthe experiment was left with the COP AL the same day."},{"index":17,"size":104,"text":"• A more complete report on each experiment was sent later to each researcher and extension worker assisting the COP AL in the interpretation of the results, its presentation to the larger community, and more important, the drawing of conclusions and proposals for the second experiment .. In the majority of the trials evaluated, results obtained with the agronomic evaluation were consistent with those obtained in the subjective evaluations made by the farmers. Their choices were supported by yield and dry matter content data. However, in sorne cases, it was clear that farmers' choices were not necessarily those options with the best agronomic results."},{"index":18,"size":64,"text":"This fact helped fanners to gain awareness about the importance of diversifying the technological options available for them and increasing the number and the frequency of technologies tested in their communities. In these cases, farmers reacted very enthusiastically and showed great interest to continue the testing and adaptation process with the technological option that showed good potential to be incorporated in their farming systems."},{"index":19,"size":266,"text":"Appendix 1 presents more detailed information on the participatory technology testing trials evaluated by the COP ALs during the 1995-96 growing cycle. The objective of the experiment was to evaluate six cassava varieties for resistance/tolerance to cassava green mites (CGM). This had been prioritized by farmers as the main constraint for cassava production in the region. The six varieties were selected locally by the farmers from genetic materials that they have planted over the years. This experiment did not include any variety from EMBRAPNCNPMF. Farmers in this community represent an atypical example of cassava growers since they are used to put heavy amounts of fertilizers in their crops ( cassava, citrus and passion fruit) and ha ve been doing it for many years. The excellent results obtained in this experiment confirm this. Figure 3 .2. 1.1 presents the results obtained for yield (ton/ha), dry matter content (ton/ha) and the preference ranking that farmers made of the treatments included in the experiment. Two of the varieties gave yields higher than 35 tons, four ofthem gave yields higher than 30 tons, figures that are well over state and national average yields for cassava. The local variety, used as check in this experiment (Platina) gave the low_ est yield (27 tonlher) although farmers ranked itas 2nd in their preferences. The two varieties that gave higher yield were ranked by farmers in 3rd and 4th place. Finding out about the excellent performance of other varieties different from the local one was one of the main conclusions and lessons learnt by the members of this COP AL and their collaborating farmers."}]},{"head":"Participatory Evaluation of Technology","index":7,"paragraphs":[{"index":1,"size":43,"text":"T o increase farmers knowledge about CGM and to create local capacity for making sound decisions about cassava crop management, farmers from this COP AL were trained to identify the CGM, and to malee field evaluations (damage score) ofthe level ofincidence ofthis pest."},{"index":2,"size":133,"text":"Farmers were then able to perform their own weekly evaluations on the pest attack and each variety was ranked according to the incidence of the pest. The information obtained by farmers was sent to the CNPMF entomologist assisting them who prepared a final evaluation ofthe CGM incidence during the cropping cycle, the cumulative damage score (Figure 3 .2.1.2). lt can be observed from this data the good tolerance of the local varieties to mite damage, the main reason for its popularity among farmers. However, this local variety did not give the best yield, and sorne of the introduced varieties that showed medium tolerance to mites were more productive. These results were enthusiastically discussed by the farrners who realized the possibility of introducing and adapting new, more productive cassava varieties into their farming systems."},{"index":3,"size":47,"text":"Results obtained in the experiment were discussed among COPAL members and other farrners and a second experiment was planned and planted. This new experiment include the top three varieties of the first trial as well as three new varieties recommended by EMBRAP A/CNPMF from its germplasm bank. "}]},{"head":"&.","index":8,"paragraphs":[{"index":1,"size":2,"text":"e: ::.  "}]},{"head":"COPAL: Chapada, Aporá","index":9,"paragraphs":[{"index":1,"size":54,"text":"The objective ofthe experiment in this COPAL was to evaluate the effect oftwo cassava varieties and two \"cultural\" practices (planting method) on the control of cassava root rot, a disease that has become a major constraint for cassava production in various states of Northeast Brazil. Farmers had prioritized this problemas their principal production constraint."},{"index":2,"size":43,"text":"One ofthe varieties (Osso Duro) was recommended by CNPMF researchers as a good source of resistance based on experimental results obtained in past years. The other cultivar (Cernitério) was selected by fanners as one the best genetic materials they have in the region."},{"index":3,"size":43,"text":"One of the cultural practices was recommended by researchers (planting stakes in ridges of soil) and the other is commonly used by farmers (planting on tlat soil). The experiment was planted in complete randomized blocks with four repetitions, and fertilizers were not applied."},{"index":4,"size":26,"text":"Yields obtained in this experiment were extremely low indicating the need for more intense long-tenn work in this comrnunity aimed at improving their cassava-based production system."},{"index":5,"size":155,"text":"The variety recomrnended by researchers showed a very low performance, giving the lowest yields. Low yields by this variety were also obtained in experiments in other regions during 1996 and has been attributed to a_fé;lilure in the resistance that it had shown in the past. This material is being discarded by CNPMF as a source of cassava resistance to root rot. The cultural practices results were more encouraging since the recomrnended practice, planting in ridges, gave the best results for both varieties. The local variety planted in ridges gave 44.6% more yield than with flat planting, and the introduced variety produced 25.5% more when planted on ridges. This recommendation, which is not currently used by fanners in the region, could be the basis offuture technology adaptation work. Fanner evaluation ofthe experiment (preference ranking), was consistent with the agronomic results, selecting as their best choices those treatments that gave the best agronomic results (Figure 3.2. 1.3)."},{"index":6,"size":103,"text":"Future work in this community would be a great challenge for PROFISMA, collaborating institutions and for the COP AL itself The community is one of the poorer fanner groups, and they are using cassava varieties that ha ve extreme} y low productivity. It is surprising to notice that a few kilometers away there are other communities with varieties that are three or four times more productive. The future role of the COP AL could be crucial in the strategy of introducing and adapting better cassava varieties and improved cultural practices with the overall objective of improving cassava production, productivity and farmer in comes. "}]},{"head":"COPAL: Buril, Crisópolis","index":10,"paragraphs":[{"index":1,"size":159,"text":"The prioritized problem in this community was also the incidence of cassava green mite (CGM). The objective of the experiment was to evaluate six cassava varieties for a resistance to CGM. Four ofthe cultivars were directly introduced from the CNP\"MF germplasm bank  • 128-08  with the mixture of organic plus chemical. Chemical fertilizer alone with this variety gave the lower yield ofthe whole experiment. Results with the other variety (Cigana Preta) were even more interesting since the best yields were obtained without fertilizers. However, the other variety with organic compost yielded 4 7% more. In relation to dry matter yield, the same tendency was observed, with the organic fertilization of the variety Cidade Rica showing the best yield (about 67% more dry matter yield per ha than the rest ofthe treatments). Farmer evaluation of the experiment (preference ranking}, was consistent with the agronomic results, selecting as their three best choices these treatments with the best the best agronomic results"},{"index":2,"size":41,"text":"Based on these results, the main point of discussion among COP AL members, other farmers and technicians was about the convenience of using fertilizers, especially chemical in cassava production. Farmers argued that this fertilizer is easy to get and sometimes cheaper.   "}]},{"head":"COPAL: Umbuzeiro, Anguera, Babia","index":11,"paragraphs":[{"index":1,"size":143,"text":"Tbis COPAL is the only one ofthose established with PROFISMA's support in which the majority of the farmers are women. Cassava producing and processing in this community is done mainly by women who work on small pieces ofland, usually rented. Farmers prioritized low productivity and poor fertility of their soils as the constraints on which they would like to work. Considering the lack of economic resources of the group, it was decided during the planning stage that the main objective of the experiment would be to test the effect of planting cassava inter-cropped with legumes which could help to improve soil fertility. The two legumes chosen were cowpea (Vigna unguicul/ata) and jack bean (Canava/ia ensiformis). To facilitate crop management the double-row planting system was introduced. Farmers decided to use their best local variety, and the experiment was planted in three different farmer fields."},{"index":2,"size":170,"text":"Results obtained indicated the high degree of complexity when an attempt is made to modify a local, traditional farming system. In this case, the use of the two legumes associated with the cassava crop demanded certain specific management, especially the timing of the pruning, which was not clearly understood by the farmers, and even by the technicians giving technical assistance to them. Due to different problems, the technicians were not able to maintain a systematic, periodic presence in the community to advise farmers' decision-making on management of the experiment. As a consequence, these two legumes were allowed to grow beyond flowering stage. Competition with cassava was very severe, especially during a drought period that affected the region in the early stages of the experiment, and cassava yields were very low. The two treatments without legumes resulted in higher yields, and the introduced double row planting system was slightly better than the traditional, single row system. Farmers' preference ranking evaluation system was consistent with the agronomic results (Figure 3 .2.1. 8)."},{"index":3,"size":125,"text":"12 \"' The lesson leamt by the researchers and extension workers giving technical assistance and advice to the farmers was very irnportant. lt became clear that there is a need to maintain a systematic, periodic presence in the community to advise the COP AL farmers, especially in those moments in which they are forced to make decisions about crop management in farming systems and practices that are new to them. Another irnportant conclusion was that during the initial experiences of farmer groups. as researchers it does not seem appropriate to mix too many treatments (for example, planting distances, inter-cropping, etc.). It is better to initiate the work as simply as possible allowing farmers to gain experience little by little as the work becomes more complex."},{"index":4,"size":61,"text":"Farmers discussions after the harvest and evaluation oftheir experiment indicated their desire to introduce improved cassava varieties in their future activities. It is expected that genetic material which is currently available at CNPMF's germplasm bank and that has been especially developed for these semiarid, low soil fertility ecosystems will be fundamental in the continuation of the work by this COP AL."}]},{"head":"S tate of Ceará","index":12,"paragraphs":[{"index":1,"size":5,"text":"COPAL: Nova Veneza, Ubajara, Ceará"},{"index":2,"size":114,"text":"The community ofNova Veneza is composed by 120 families and is located in the Serra de Ibiapaba, a region characterized by a relatively good annual rainfall and moderate climate which allows year-round production of various cops such us sugar cane, fiuits, com, beans and cassava. The importance of cassava in the region is mostly for farmers ' own consumption of cassava flour (farinha de mandioca) since the other crops are more important as a cash and income source. Nonetheless, cassava is widely grown in the region, and the COP AL in this community identified as the main production constraint the lack of improved, more productive varieties and altemative, more efficient cropping practices, especially fertilization."},{"index":3,"size":34,"text":"Additionally, cassava production in the region has been affected drastically during the last five years by the disease known as mycoplasm witches' broom (WB) which caused asevere reduction in production, productivity and area planted."},{"index":4,"size":288,"text":"Fanners included two local varieties in their experiment: one, Cruvela, is a local cultivar widely grown in the region and the other, Buja de Olho Roxo, was introduced as one ofthe varieties that shows sorne tolerance to WB. The experiment was planted with a randomized block design with six treatments and three repetitions. The two main characteristics of the experiment were the introduction of two legumes: Crotalaria and pigeon pea, as sources of green manure, and the use ofCompost, a practice that the Extension Service (EMATERCE) is promoting intensively in the region. The results of the experiment are presented in Figure 3.2.2.1. It can be observed that the introduced cultivar, Olho Roxo gave higher yields for all treatments (an average increment of 48% for the whole experiment), and all the treatments in which the compost was utilized al so gave higher yields ( an average increase of 128% for the variety Cruvela and of 41% for the variety 01ho Roxo. The overall best result was obtained by intercropping cassava with pigeon pea and using compost. This practice compared with the traditionaJ system of planting cassava alone gave a yield in crease of 225% for the variety Cruvela and of 69% for variety Olho Roxo ). Results obtained with dry matter content showed the same trend suggesting a beneficia) effect of the legume and the compost on the dry matter content ofthe cassava roots. It has been reported in the literature that pigeon pea is one ofthe few legumes that has a unique mechanism that allows them to access phosphate that is bound to caJcium and iron soil particles. These legumes release acids from their roots which react with caJcium-bound and iron-bound phosphate to release phosphate for plant uptake."},{"index":5,"size":12,"text":"AdditionaJly, their deep rooting characteristic has a positive effect helping water infiltration."},{"index":6,"size":137,"text":"Preference ranking evaJuation conducted by fanners was somehow different from the agronomic results. Fanners gave selected as their best choice, for both varieties, a treatment which was the third place in yields and dry matter content. Their choices for the worse treatment did coincide with the agronomic evaJuation (Figure 3  The objective defined by the COP AL for its first experiment was then related to this problem. They were getting very enthusiastic about sorne hybrids that have started to come out from these activities and decided to test the one they liked best, the hybrid 8709-02 (local name is Salamanta), anda local clone named Cabelo de Velha. The experimental design also included the use ofthe legumes pigeon pea and Crotalaria and compost as fertilizer. The total number of management treatments was six, with three repetitions for each."},{"index":7,"size":247,"text":"The results obtained in the experiment were completely different for the two varieties. The hybrid Salamanta confirmed that it has indeed a great potential in the region giving higher yields than the local clone in five of the six treatments. The average yield for this hybrid for the whole experiment was 79% higher than average yield with the local variety. Considering the effect of the compost on yields, for the hybrid Sal amanta, it can be observed that average yield for the three treatments that have compost was 20% higher than these respective treatments without compost. The trend for the local variety was totally opposite, with the treatments without compost giving an average yield 55% higher than these respective treatments that were fertilized with compost. This data seems to suggest that there is a genetic difference in the response to fertilizer because in both cases, the compost was prepared at the same time and applied at the same rates. The intercropping with pigeon pea was the best treatment for the local variety and was the second best one for the introduced hybrid, confirming the beneficial effects of this practice on cassava yields. The dry matter content results showed the same pattems as the yield data for both varieties. Comparing the local, traditional planting system with the best treatments for each variety, it can be observed that for the introduced hybrid the maximum increase in yield was 26.5% whereas for the local variety this was 46.8% (Figure 3.2.2.2)."},{"index":8,"size":69,"text":"Preference ranking evaluation conducted by farmers was contrasting for both varieties. In the case of the introduced hybrid, although the local planting system had the lowest yields, farmers ranked it as their second choice, only exceeded by the treatment that included compost only. With the local vari~ty, farmers's opinions generally matched the agronomic results, and their best two options were exactly those with highest yields (Figure 3.2 .2 .2)."},{"index":9,"size":147,"text":"Although the introduced hybrid was ranked equally with the local variety when each was planted alone, it was rated lower than the local variety when cultivated with compost (with or without pigeon pea)-despite the fact that yields were higher by 67 to 77%. The discrepancy between farmer ratings and yield indica tes the importance of using additional measures of crop characteristics to evaluate and select germplasm. The main conclusion of this experirnent is the ratification of the great potential that this hybrid seems to ha ve for the cassava systems in the region. CNPMF is intensifying its work on further testing, multiplication and release among farmers, as well as maintaining germplasm development activities to find similar or better genetic materials. In early 1997, a Field Day is plannedjointly between CNPMF, local institutions and the COP AL to officially deliver this hybrid to cassava growers in the region."}]},{"head":"Cl40","index":13,"paragraphs":[{"index":1,"size":1,"text":".1::"},{"index":2,"size":3,"text":"... 30 8."},{"index":3,"size":5,"text":"., 20 ª e 10 "}]},{"head":"COPAL: Vila Moura, Acaraú, Ceará","index":14,"paragraphs":[{"index":1,"size":75,"text":"This community is located in the semi-arid region of Ceará, a drought-prone area in which limited rainfall gives farmers very few agricultural options, among which cassava is on top of the list. Cassava production in the region is practiced intensively with a growing period that in average exceeds 20 months. Farmers argue that cassava production with just one \"winter\" is not profitable (rainy season) and plants are usually allowed to grow during the second year."},{"index":2,"size":58,"text":"The COP AL defined as its experimental objective the testing of organic compost as fertilizer in cassava production mixed with two legumes Gack bean and velvet bean). The two legumes were intended to be used as mulch and the experiment included the use of compost and a planting arrangement in double rows to facilitate farmers' management ofthe experiment."},{"index":3,"size":72,"text":"Since the main objective was to increase farmers ' knowledge about the management ofthis new system, and especíally of the two legumes, the farmers decided to harvest the experiment after one year. The best two local varieties were used. The experiment was planted in randomized blocks with six treatments and three repetitions. A similar experiment was planted in the second year switching positions between the cassava and the legumes in each plot."},{"index":4,"size":16,"text":"Evaluation ofboth experiments did not include determinations of dry matter and farmers ' preference ranking evaluation."},{"index":5,"size":146,"text":"The results ofthe experimentare presented in Figure 3.2.2.3 . It can be concluded from the data obtained that cassava production in the region with just one growing cycle gives indeed very low yields. The best results with both varieties were obtained using compost without legumes. The use of velvet bean as mulch was practically null due to severe attacks ofleafcutting ants that destroyed it. The adaptation of jack bean to the dry clima te was very good, but it became evident that sorne management changes have to be introduced because it competes severely with the cassava crop. Probably the best option is to use just two rows in between the cassava plants and increase the spacing. Nonetheless, farmers were very impressed with the growth of this legume and especially with the concept of growing a plant to be, later on, cut and incorporated into the soil."},{"index":6,"size":51,"text":"The best yield in both experiments was obtained with the variety Fragoso, in the treatment cassava alone + compost (13.45 ton/ha), a yield which is around the average in the region for two cycles. Sorne conclusions were evident for the members of the COP AL based on the results ofthis experiment:"},{"index":7,"size":4,"text":"12 10 ca 8"},{"index":8,"size":1,"text":".::"},{"index":9,"size":34,"text":"... • In the region farmers are used to plant corn and beans intercropped with cassava and this malees the use of legumes for soil fertility recuperation more difficult to be adopted by farmers;"},{"index":10,"size":12,"text":"• Compost use proved to be an attractive, cheaper option for farmers;"},{"index":11,"size":33,"text":"• There is a need to study the econornic viability of planting varieties with short growth period (harvest in one cycle ), -using organic compost. This system gave higher yields in this experiment."},{"index":12,"size":7,"text":"COP AL: Lagoa Grande , Acaraú, Ceará "}]},{"head":"Exploration for natural enemies","index":15,"paragraphs":[{"index":1,"size":123,"text":"Explorations in 1996 were conducted to find phytoseiid predatory mites in two target ecological zones: 1) hot semi-arid ( corresponding to NE Brazil) and 2) high altitude/subtropical (corresponding to the East African plateau). For the hot semi-arid target, we collected 5 species of phytoseiids in Manabí, Ecuador from 11 sites with 425-1500 mm annual precipitation, 6-9 dry months (<60 mm rain), 24-26°C average temperature, and 16-120 m elevation. For the high altitude/subtropical target, we collected 6 species of phytoseiids from 20 si tes in Antioquia, Boyaca, Caldas, Cundinamarca, Quindio, Risaralda, Santander, and Tolima, Colombia from sites with 425-1500 mm annual precipitation, 0-4 dry months, 14-26°C average temperature, and 495-2216 m elevation. We establíshed 7 new colonies of phytoseiids from high elevations for evaluation."},{"index":2,"size":12,"text":"A culture of Typhlodromalus aripo from Palmira was established for biological investigations."},{"index":3,"size":234,"text":"This appears to be the most effective of the three mi te predators established in Africa, yet little is known about why it is so effective. Also there appear to be two kinds of \"T. aripo\" which differ in their biology and may actually be different species.      ~ 10   Phytoseiid species that are candidates for exportation as biological control agents were evaluated for the specificity of prey and food sources that they can consume. This is to assure that we select species that will not harm non-target hosts after being imported to Afiica or Northeast Brazil. The ability to use pollen or sugary exudates of cassava leaves, mealybugs or whiteflies is an advantage in helping to maintain predator populatíons when cassava green mites are scarce. Galendromus annectens and G. helveolus showed much higher longevíty in the presence oftetranychid prey (Mononychellus caribbeanae or Tetranychus urticae) than for the other food sources tested (Fig. 4.1.5). Neoseiulus idaeus was similar except that it could also utilize pollen from castor bean (Ricinus communis). Typhlodromalus tenuiscutus, Euseius ho and T aripo could use a greater varíety offood sources, including cassava exudate (a sugary liquid found on leaves), immature whiteflies (Aleurotrachelus socialis) and mealybugs (Phenacoccus herreni); both of which produce sugary exuda te. Predatory mites must consume protein in order to produce eggs, so fecundity is an important measure of the suitability of different food sources to increase predator populations."},{"index":4,"size":145,"text":"Typhlodromalus tenuiscutus showed the highest specificity, laying substantial numbers of eggs only when fed on cassava mites,Mononychellus caribbeanae (which has previously been shown to be equal to M tanajoa in preference and suitability). Neoseiulus idaeus, Galendromus annectens and G. helveolus also had high fecundity when provided with the two-spotted spider mite, Tetranychus urticae (Fig. 4. 1.6). Euseius ho was the only species ofthis group that could produce many eggs when fed only castor bean pollen. Typhlodromalus tenuiscutus and Euseius ho could also reproduce at low rates when held on cassava leaves infested with various developmental stages of immature whiteflies (Aleurotrachelus socia/is) .   Benin via quarantine at the University of Amsterdam (Mitox). Climatic parameters associated with the sites from which the predators were collected were estimated from the average long-term data for the four nearest climate stations, weighted by the inverse ofthe distance squared (Table 4.1.3)."},{"index":5,"size":27,"text":"To date, three species ofphytoseiids have been established in Afiica. Ofthese, T. aripo and T. manihoti are spreading rapidly and are reducing cassava green mite populations significantly."},{"index":6,"size":63,"text":"Typhlodromalus aripo is estimated to be increasing root yield by 3 0%, which is equal to about US $70 per season. Estimated benefits for 4 countries in West Afiica are on the order ofUS $60 million per year. Two species released in Northeast Brazil (T. tenuiscutus & N californicus) have been recovered in small numbers, the latter up to 4 months after release."},{"index":7,"size":35,"text":"Typhlodromalus manihoti and cassava green mite (CGM) were also sent to the University of Amsterdam, and CGM was sent to Boyce Thompson Institute, Ithaca, New York to establish colonies in support of collaborative basic research.   "}]},{"head":"Clima tic distribution of phytoseiids","index":16,"paragraphs":[{"index":1,"size":213,"text":"Explorations for phytoseiids have been conducted in 14 countries in Latin America and the Caribbean with samples from over 1,097 sites. Over 87 species ofphytoseiids have been encountered and over 25 new species have been described. About 67% ofthe samples carne from cassava and 76% ofthe 2,943 phytoseiid records are also from cassava. Colombia, Ecuador and Venezuela account for 89% of these records, comprising at least 77 species of phytoseiids, with at least 44 in association with cassava. Because of the high number of samples and the geographic diversity of this region we chose to use it for ecological analysis. The clima te of each sample site was estimated using long-term climatic data from the CIAT GIS (geographic information system) database (average of 4 nearest climate stations weighted by distance-2). Duration of dry season (no. ofmonths with <60 mm precipitation) and elevation (m above mean sea level) were considered the most useful climatic parameters available for classifying the sites. This choice was based on availability of information and usefulness for evaluating species to release in target climatic zones. Data are reported as incidence (number of samples of a climatic classification in which the species was present divided by the total of such samples in that classification) to adjust for sampling effort (Table 4.1.3)."},{"index":2,"size":94,"text":"A higher number of species were encountered in Colombia than expected based on sample effort, which probably reflects the high variation in topography and climate found within the country. In general, we have few samples from high altitude dry sites, which limited the climatic analysis. The phytoseiid species found in most environments (wet and dry, high and low) were Typhiodromalus manihoti and T aripo (Table 4.1.4). Species found more commonly in dry regions were Euseius ho, Gaiendromus annectens, Typhiodromalus rapax, T tenuiscutus, and Neoseiulus idaeus. Species found at intermediate e1evations were Galendromus annectens, G."},{"index":3,"size":51,"text":"heiveolus, and Euseius concordis, while Typhiodromalus neotunus and Euseius naindaimei occurred at high elevations. Two species appeared geographically isolated: Typhiodromaius tenuiscutus and Neoseiulus ca/ifornicus, and they were strongly recommended for release in Northeast Brazil, where they do not occur. These are the species that were released there in 1995 and 1996. "}]},{"head":"Pbytoseiid associations witb cassava","index":17,"paragraphs":[{"index":1,"size":129,"text":"The previously described database of exploration records for phytoseiid mites was analyzed to leam more about the host plant associations ofphytoseüds. About 76% ofthe 2,943 phytoseüd records are from cassava, so relatively little can be said about associations with plant species other than cassava. Colombia, Ecuador an9 Venezuela account for 89% of these records, and were selected to restrict the geographic range for this analysis. In this subset, 81 .5% of the records are from cassava. The 2,084 records were classified as coming from either cassava or \"other\" host plant and analyzed by chi-square. Most ofthe host plants had only 1-3 records per phytoseüd species, so it is not worth looking at more than the aggregated \"other\" plant category. The 17 most frequently encountered phytoseiid species are listed in  "}]},{"head":"Evaluation of Neozygites","index":18,"paragraphs":[{"index":1,"size":62,"text":"Natural outbreaks ofthe fungal pathogen Neozygites c.fjloridana in Northeast Brazil have been observed to rapidly kili off populations of cassava green rnite (CGM, M tanajoa). Although subsequent investigations by ITT A scientists have shown that apparently the same species occurs in Africa. The lack of virulent epizootics suggests that it would be worthwhile to introduce a more virulent strain from South America."}]},{"head":"Pathogenicity of Neozygites strains","index":19,"paragraphs":[{"index":1,"size":59,"text":"Cultures of the fungal pathogen Neozygites c. f floridana were collected from the cassava green rnite and two-spotted spider rnite (Tetranychus urticae) at CIAT and from CGM at Media Luna, Colombia. Other cultures obtained from Brazil and Africa were included in a laboratory evaluation ofhost specificity on three rnite species: M . tanajoa, M . caribbeanae and T. urticae."},{"index":2,"size":126,"text":"Single mi te mumnúes were placed in the center of a cassava leaf disk under conditions of high hurnidity (95%) and 16 hours of darkness to produce conidia. Twenty-five recen ti y emerged female mites were placed on the disk to be exposed to the conidia for 2 d at 65% RH, 12 h photoperiod. Afterwards they were transferred to fresh leaf disks and were examined daily for signs ofinfection and mortality. None ofthe 3 strains fromM tanajoa infected T. urticae, and one ofthe strains from T. urticae failed to infectM tanajoa (Fig. 4.1.7). AH 5 strains infectedM caribbeanae. This confirms that ther~ _ is substantial difference among the strains and that those isolated from Mononychellus appear to be more specific than those from T. urticae."}]},{"head":"Geographical distribution of Neozygites","index":20,"paragraphs":[{"index":1,"size":101,"text":"This pathogen is currently being studied for use as a biological control agent of CGM, but little is known about its geographic distribution or host range. We reviewed 10,782 specimens of tetranychid mites on microscope slides from our museum collection, representing 907 sample sites, to determine the host range and geographic range of this pathogen. These specimens were previously collected during foreign exploration for natural enemies of M tanajoa. Both conidia and hyphal bodies can be detected in the slides. Signs of Neozygites infection (presence ofhyphal bodies) was observed in 14 species oftetranychid mites from 11 neotropical, 2 African and 2"},{"index":2,"size":54,"text":"Asían countries, indicating that this pathogen may be much more important than was previously thought (Tables 4.1.6 and 4.1. 7). Neozygites infection was also observed in Tetranychus kanzawai specimens from China and Indonesia. The highest frequency of infection, as indicated by the presence ofhyphal bodies, was found in M caribbeanae andM tanajoa (Fig. 4.1.8)."},{"index":3,"size":71,"text":"Significantly low frequencies occurred in 0/igonychus peruvianus, which is common on cassava but which is generally protected beneath silk webbing, and Tetranychus sp. (which is probably mainly T. urticae, which cannot be identified to species without males). Although it is not certain that only one species of Neozygites is represented by these results, they are in agreement with the previously described laboratory pathogenicity tests for N c. f jloridana indicating that"},{"index":4,"size":19,"text":"Mononychellus is very susceptible compared to other tetranychids.     Neozygites before neotropical strains ofthe fungus can be released in Africa."},{"index":5,"size":27,"text":"Characterization ofDNA using PCR-based techniques should be able to permit the identification of individual strains; however, this has never been done with this genus of fungus ."},{"index":6,"size":181,"text":"Despite the obstacles that are normally encountered in such pioneering research, substantial progress has been made. In vitro culturing methods developed by Don Roberts (Boyce Thompson lnstitute, USA) and Luis Leite (Instituto Biologico, Brazil) have been successfully adopted and modified. We can now grow strains of the fungus from both T. urticae and M tanajoa (Roberts & Leite could only grow a T. urticae strain) on artificial media (Grace's Insect medium + yeast extract + lactoalbumin). Problems with bacterial contamination have been resolved by adding antibiotics to the media (Fig. 4. 1.9). This has removed a major obstacle to our work, now permitting us to produce ~~fficient quantities ofuncontaminated DNA. Nevertheless, the growth rate of strains isolated from M tanajoa still grow very slowly (Fig. 4 . 1.1 0). Because the Neozygites strains isolated from M tanajoa appear to be more specific in host range than those from T. urticae, this suggests that growth rates may be improved by further refinement of the growth media, perhaps by induding compounds found in cassava leaves. Futher work will be done in this area."},{"index":7,"size":13,"text":"Five strains of Neozygites c. fj/oridana were multiplied in vitro for DNA extraction."},{"index":8,"size":159,"text":"Preliminary evaluations using RAPD (random amplified polymorphic DNA) and AFLP (amplified fragment length polymorphism) techniques have been performed. The initial RAPD trials using 5 primers (A2, A3 , B2, B9 & D2; Operon Technologist, La Jolla, CA) were able to distinguish Neozygites c.f floridana from a distantly related fungus (Phaeoisariopsis griseo/a, bean angular spot), but not among T urticae strains of Neozygites. The AFLP method generally provides many more bands (DNA fragments), thus increasing the power to detect differences. An unreplicated AFLP trial showed strong differences among 5 Neozygites strains, while the pattems for different samples from a single batch of one strain were clearly identical. Confirmation of these results will mean that we can readily identifY individual strains of this pathogen, thus opening the way to make releases in Africa. A strain of Neozygites sp. from T. urticae was released to Biocontrol, SA and Coinbiol, SA, in Palmira, Colombia for possible development as a commercial biological control agent."}]},{"head":"Phytoseiid mass rearing techniques","index":21,"paragraphs":[]},{"head":"Mass rearing of Typhlodromalus tenuiscutus","index":22,"paragraphs":[{"index":1,"size":155,"text":"Experiments were conducted to help optimize the use of the Mesa-Bellotti method of rearing phytoseiid predators to assist mass-rearing of predators in NE Brazil. This system consists of using small plastic containers with a screen shelf Fresh mite-infested leaves are placed in the bottom ofthe container to feed the phytoseiid predators. After 2-3 days additional fresh, rniteinfested lea ves are added on top of the shelf The predators then move from the old lea ves to the new leaves, which are removed in 2-3 days, when the next batch offresh mite-infested leaves are added. This system was designed specifically for predators that require Mononychellus prey, which must be grown on cassava leaves. This particularly applies to Typhlodromalus tenuiscutus which we are now releasing in NE Brazil. The experiment on colony production was initiated with 50, 100 and 200 females in Mesa-Bellotti trays, and adult females were harvested weekly for 8 weeks, starting at week 3."},{"index":2,"size":118,"text":"An experiment was conducted to measure the effect of initial number of T. tenuiscutus females used to establish Mesa-Bellotti mass-rearing cultures on the number of adult female progeny harvested. After the third week of rearing, all adult females were counted and removed from the rearing system. It can be seen that this method results in a continued decrease in production of the culture, which suggests that not enough females are retained by this harvesting method to sustain levels of oviposition (Fig. 4. l . 11 . ). The highest production of females from Mesa-Bellotti cultures was from those initiated with 1 00 females, the least from those started with 50 females Weeks sin ce initiation of the culture     "}]},{"head":"Phytoseiid taxonomy","index":23,"paragraphs":[{"index":1,"size":105,"text":"Taxonomic key to cornmon species 78 A taxonomic key to 30 phytoseiid species cornmonly found on cassava in northem South America was developed in collaboration with Gilberto de Moraes (CNPMAIEMBRAP A, Sao Paulo, Brazil) (Table 4.1.8). Phytoseiids collected in the field during explorations and experiments were identified and curated. The taxonomic collection is being reviewed to verify old identifications and correct the computer database. 79 Amplified fragment length polymorphism (AFLP) analysis of genetic variation showed that geographic strains of N idaeus were very homogeneous whereas those of T. manihoti differed greatly. These results are similar to the genetic variability shown in isozyme analysis of esterases."},{"index":2,"size":31,"text":"This suggests that T manihoti is either a very plastic species or may represent a group of cryptic species. Futher studies on genetic crosses between strains ofthe species are being conducted."}]},{"head":"Cassava CD-ROM","index":24,"paragraphs":[{"index":1,"size":13,"text":"We scanned and formatted 11 majar documents (2,800 pages) including recent CIAT Cassava"},{"index":2,"size":11,"text":"Program annual reports, CIAT Working Documents, scientific meeting proceedings and Cassava"},{"index":3,"size":41,"text":"Newsletters to be included in a CD-ROM being published by liTA and the University ofFlorida, Gainesville (Table 4 .1. 9). effective due to these parasitoids that cassava production has retumed to so me of the areas where it had been abandoned."},{"index":4,"size":48,"text":"In the Llanos of Colombia and Venezuela, cassava is attacked by P. herreni, causing crop losses. Studies to evaluate the effectiveness ofbiological control were conducted in Villavicencio in collaboration with CORPOICA/La-Libertad. This research fonned part ofa MS thesis requirement for a Colombian student from Georg-August University, Gottingen, Gennany."},{"index":5,"size":78,"text":"Field experiments were initiated by artificially infesting cassava plants with P. herreni to insure adequate mealybug populations. Three parasitoid species, A. vexans, A. diversicornis and A. coccois were subsequently released in 3 cassava fields; one parasitoid species per field. In a fourth field all 3 species were released. In control plots, cassava growing tips were protected from parasitoids with a gauze sleeve cages. The percentage of parasitism was obtained by dissecting 1,887 2nd, 3rd and 4th instar mealybugs."},{"index":6,"size":57,"text":"The study resulted in parasitism rate of 15.5% anda leve! of encapsulation of37.6%. In this experiment low mealybug densities produced higher percentages of encapsulation, while a higher mealybug population caused Iower percentages. The parasitoid A. vexans had the highest percentage of parasitism. In addition, parasitism rates were highest in the field where all three species were released."},{"index":7,"size":6,"text":"Chemical Mediated Searching Behavior of Parasitoids."},{"index":8,"size":13,"text":"Plants when attacked by insects often release volatiles that can attract natural enernies."},{"index":9,"size":87,"text":"Previous results from this on-going research have indicated that two parasitoid species A. vexans andA. diversicornis respond significantly to infested plants. A. coccois was not attracted more to infested plants than to uninfested ones, though it was attracted by cassava plants in general. More recent research using Y -tu be olfactometer experiments ha ve tried to determine the cause of the insect attraction: \"synomones\" released by infested cassava plants or odors emitted by the mealybug and íts by-products. The following choices were offered to A. vexans andA."},{"index":10,"size":77,"text":"diversicornis: infested vs. washed infested leaves (Cl), Blank vs. Cl, and healthy vs. Cl. To obtain clean leaves (Cl), mealybugs and exuviae were removed from two infested cassava leaves and leaves were thoroughly washed with wet cotton to remove honey dew and fungi . For the Mb treatment, all products originating from the presence of mealybugs were removed from two infested cassava lea.ves. Mealybugs and exuviae were deposited on wet cotton, and honeydew and fungi were collected."}]},{"head":"82","index":25,"paragraphs":[{"index":1,"size":70,"text":"Initial results indicate that both parasitoid species are attracted to the infested leaves (Cl) over the mealybug (Mb). A significantly higher proportion offemale parasitoids ofboth species chose the infested but cleaned leaves over the blank (no leaf) or the mealybug and its exudates. There was no significant differences in the Cl vs. healthy leaves or the Cl vs. infested leaves, indicating that plant volatiles from mealybug-damaged leaves attract the parasitoids."},{"index":2,"size":91,"text":"Field experiments, to determine if a bean intercrop will have an influence on the capacity of two parasitoids A. vexans andA. diversicomis, to parasitize P. herreni on cassava were initiated during 1996. Three treatments were tested, plots with only cassava plants, plots with mixed cassava and beans, and plots with only bean plants. Eight potted cassava plants infested with second and third instar mealybugs, were placed in each plot and 20 parasitoid females of one species were released. After five days, plants were brought into the greenhouse and parasitism was deterrnined."},{"index":3,"size":55,"text":"Initial results show that the parasitism rate of A. vexans is higher than A. diversicomis, but the difference may not be significant. In addition A. vexans appears to have a better searching capacity in pure cassava stands, while A. diversicomis appears to prefer the bean crop, but more data is needed to verify these results."}]},{"head":"Whiteflies","index":26,"paragraphs":[{"index":1,"size":23,"text":"Aleurotrachelus socialis, Bemisia tuberculata and Trialeurodes variabi/is are the most common species of whiteflies attacking cassava in Colombia. Previous surveys show that A."},{"index":2,"size":40,"text":"socia/is is the predominant species, and can cause severe cassava yield reductions when high populations occur. For the past two years, considerable survey work has been undertaken to more accurately define the pest distribution and its associated natural enemy complex."},{"index":3,"size":45,"text":"Results from these Colombian surveys (the 3 zones extensively surveyed: the Andean zone, the Llanos, and the North Coast (Caribbean) are deseribed in the 1995 Annual Report) show that A. socia/is and B. tubercu/ata have the widest distribution and are found in all areas surveyed."},{"index":4,"size":30,"text":"They are usually found in lower altitudes, sharing the same elimatie eonditions and altitudes most favorable for the eassava erop. T. variabilis was not observed in the Llanos (eastem savanna)."},{"index":5,"size":27,"text":"High altitudes above 1,000 meters sueh as the Andean region favored this speeies. Neither temperature nor relative humidity were factors related to populations ofthe three speeies. A."},{"index":6,"size":14,"text":"socialis was found mostly in those si tes with temperatures above 3 5° C."},{"index":7,"size":56,"text":"Numerous mierohymenopteran parasitoid natural enemies found assoeiated with eaeh speeies of whitefly were eolleeted and identified. Several were new speeies reeorded from Colombia, and others were unreeorded speeies. The highest level of parasitism was found on A. socia/is in the Llanos at 15 .3% ofthe pupae parasitized. The highest levels ofparasitism for T. variabilis and B."},{"index":8,"size":14,"text":"tuberculata were in the Andean Region with 12. 1% and 13 . 9%, respeetively."},{"index":9,"size":16,"text":"Ten speeies of parasitoids were reeovered from the three whitefly speeies (Table 4 . 2. 1)."},{"index":10,"size":43,"text":"Seven of these were reeorded for the first time in Colombia, and four of these are new, undeseribed speeies, reeorded for the first time to seienee. Encarsia hispida (Aphelinidae) was the predominant parasite with 64.2% ofthe total parasites eolleeted. Three speeies ofthe genus"},{"index":11,"size":31,"text":"Eretmocerus are new undeseribed speeies (referred toas Eretmocerus sp. \"a\", \"b\" and \"e\"). The other new species E. be/lottii was found parasitizing A. socialis and T. variabi/is in the Andean region."}]},{"head":"Eretmocerus","index":27,"paragraphs":[{"index":1,"size":52,"text":"These results further indicate the great potential for arthropod biodiversity that exists in agroecosystems, that is yet undiscovered and need to be further explored. Research on the behavior of these parasitoids has been initiated.  O without root rots 1980-83 1984-87 1988-91 1992-95 Root rot development of cassava cultivar MBRA-12 at CIA T."},{"index":2,"size":130,"text":"Random samples were taken from affected plants at the farms visited during the survey of 4 departments in Colombia. Phytophthora spp. was isolated by direct plating of diseased plant tissue on selective media and by baiting with a selective host. For direct plating small fragments were placed on V8 juice agar (V8A) and Potato-Dextrose Agar (PDA) amended with thiabendazole (0.5 j.!llml), benomyl (20 j.!g/ml), ampicillin (250 j.!g/ml), penicillin (400 j.!g/ml) and rifampicin (1 O j.!g/ml). The baiting technique was as follows : soil or macerated plant tissue was suspended in sterile deionized water, and cassava sprout fragments of approximately 2 cm were placed in the suspension. About 1 wk after incubation, fragments of the sprouts were placed on the described selective media. Table 4.3.1 presents a summary ofthe successful isolations. "}]},{"head":"87","index":28,"paragraphs":[{"index":1,"size":56,"text":"Isolation of Phytophthora spp. was effective using the described techniques, and 75 isolates were obtained. Preliminary inoculations of sorne of the isolates confirmed their pathogenicity to cassava. A rapid and accurate method to detect these pathogens in plant tíssue, soil and water samples is required. Research is ongoing to develop a polymerase chain reaction (PCR) method."}]},{"head":"Culture of cassava Phytophthora species","index":29,"paragraphs":[{"index":1,"size":55,"text":"It is necessary to have information about the Jaboratory culturing of Phytophthora species to determine the identity of species, to study their responses to ecological factors, and to develop inoculum for use in pathogenicity tests. Phytophthora spp. isolated from cassava grow and sporulate best on V8A compared with PDA, at 27°C, with or without light."},{"index":2,"size":11,"text":"Phytophthora cultures established from the field are always contaminated with bacteria."},{"index":3,"size":68,"text":"Therefore the following techniques were tested to obtain bacteria-free cultures: 1) placing a small piece of fungal growth on the inside of a glass Van Wiegham cell that has been placed on a selective medium~ 2) inverting the entire agar culture in a petri plate~ 3) selective weak medium (medium diluted with water). The most efficient method is transferring fungal discs to water agar that contains appropriate antibiotics."},{"index":4,"size":65,"text":"To check if a Phytophthora isolate is free from bacteria! contamination a fungal plug was transferred toa test tube with liquid medium (gllt: peptone, 5~ casamino acids, 0.5; malt extract, 0.5; pH 7.2). Ifthe culture is contaminated with bacteria, the liquid becomes cloudy within 48 h of incubation at 27°C, but ifbacteria-free, the liquid remains clear. Phytophthora spp. were successfully transferred from medium to V8A."}]},{"head":"88","index":30,"paragraphs":[{"index":1,"size":80,"text":"Single-zoosporic isolation was readily accomplished by isolation of a single germinated cyst or non-cysted zoospore after a highly concentrated fungal suspension had been spread thinly on the surface of3% water agar on a micro~c9pe slide. After 12-24 h, germinated spores were detected on the surface of the agar by use of a microscope with a magnification of 400x. With a bent Pasteur pipet, a gerrninated spore was marked, and by use of a needle a plug was placed on V8A."},{"index":2,"size":10,"text":"Activities to identify and to conserve strains have been started."}]},{"head":"Development of bioassays to study pathogen variability and to test cassava germplasm for resistan ce","index":31,"paragraphs":[{"index":1,"size":16,"text":"The results of known bioassay methods are not well correlated to field resistan ce of cultivars."},{"index":2,"size":66,"text":"Therefore 5 new in vitro and greenhouse methods ofinoculation, described in  Restriction Digest with Alul of the product amplified for the ITS region showed 3 different restriction patterns, which corresponded to the 3 species tested. DNA from 76 Phytophthora strains will be digested with Cfol, Mspl, Msel restriction enzymes to differentiate the species. In addition, RAPD analysis will be conducted to determine genetic variation among strains."}]},{"head":"Biocontrol of Root and Stem Diseases","index":32,"paragraphs":[{"index":1,"size":34,"text":"Antagonism of Trichoderma spp. and Pseudomonas spp., potential biocontrol agents, to Phytophthora spp., Diplodia manihotis and Fusarium oxysporum, the causal agents of cassava root and stem rot diseases in America and Africa, was investigated."},{"index":2,"size":8,"text":"Extracellular production of antifungal compounds by Trichoderma spp."},{"index":3,"size":29,"text":"Trichoderma spp., isolated from the rhizosphere of cassava plants were screened in vitro for antifungal activity against a range of fungal pathogens: 2 isolates of P. drechs/eri and P."},{"index":4,"size":22,"text":"nicotianae, D. manihotis and 1 ofF oxysporum. A control treatment with Thielaviopsis spp., a causal agent ofbud rot of oilpalm, was included."},{"index":5,"size":99,"text":"The activity of 14 one-week-old cultures differed among the pathogens. Production Trichoderma spp. in liquid medium Production of Trichoderma spp. using a liquid culture system on media based on molasses, V8 juice and mineral solutions was studied. These media were incubated at 30°C for 1 wk under darkness of shake culture. Of the media evaluated, a mineral salt medium supported maximum conidia production for 27 Trichoderma spp. strains. High antifungal activity was observed by culture filtrates prepared with the medium. Field plots and cassava stem cuttings, infested by Phytophthora spp., were inoculated by strains grown in the identified medium."}]},{"head":"Study on Stem Rot Disease Caused by Fusarium Species","index":33,"paragraphs":[{"index":1,"size":43,"text":"Fusarium solani and F. oxysporum strains were obtained from 86 cassava samples including stem cuttings, swollen and secondary roots, and soil obtained from different zones in Colombia (Maria La Baja, Carimagua, Media Luna, Pivijay, Calarcá, Palmira, Villavicencio, Alcalá, Pescador, Granada and Quilichao )."}]},{"head":"94","index":34,"paragraphs":[{"index":1,"size":71,"text":"In addition, 4 methods of classification were tested for differentiation of the strains, including morphology, growth, pathogenicity and site directed (rDNA) PCR. These species were compared in pathogenicity tests, in which the s~ptoms caused by individual strains were very similar, although symptom severity differed. Infected seedlings exhibited necrotic stem lesions compared with healthy controls. The majority of strains were not clearly differentiated on PDA by colony type, growth or pigment production."},{"index":2,"size":117,"text":"Amplification ofthe ITS region ofthe rDNA was obtained with template DNA from 10 strains using extracted DNA. Restriction digest with Alul, ofthe product amplified for the ITS region showed 2 different restriction pattems, which corresponded to the 2 species tested. The PCR analysis was more reliable in differentiating the strain than the other methods. In addition rDNA analysis offered a distinct advantage by requiring less time for distinguishing among the species. The simplicity ofthe PCR analysis presented in the study, and the accuracy oftheir predictions make them acceptable for identification of Fusarium species on cassava. The most pathogenic of the F so/ani and F oxysporum strains will be distinguished from the other Fusarium strains by RAPD markers."},{"index":3,"size":13,"text":"Furthermore, a screening of 51 cassava cultivars has been conducted by inoculating 28"},{"index":4,"size":5,"text":"Fusarium strains to evaluate resistance."}]},{"head":"Study on Stem Rot Caused by Diplodia manihotis","index":35,"paragraphs":[{"index":1,"size":34,"text":"A survey in cassava growing areas in Colombia was conducted in 1995-1996, and samples including cassava stem cuttings and roots were collected. 55 strains of D. manihotis were isolated and monosporic cultures were obtained."},{"index":2,"size":54,"text":"Three inoculation methods were used for pathogenicity studies, they included stem injection, stem wounding and root cylinder inoculation. Clear symptom development was observed by stem wounding. From a total of 55 strains, 8 were pathogenic on cassava plants. A pathogenic specialization study has been initiated. At the moment, 20 cassava cultivars have been inoculated"},{"index":3,"size":9,"text":"with 40 strains selected from the D. manihotis collection."},{"index":4,"size":38,"text":"additional isolates are being characterized. It can be concluded that, over the range ofCVMV, there is a significant degree of molecular diversity and that care should be taken not to spread the isolates via transportation of infected germplasm."},{"index":5,"size":5,"text":"CVMV yield loss field trials."},{"index":6,"size":155,"text":"One ofthe important questions regarding Cassava Vein Mosaic Virus (CVMV) is the effect on root yield. Since the absence of symptoms is not a reliable indicator that the cassava clone is free ofCVMV, in vitro plants were used for this yield trial experiment. The plants were grown in the EMBRAP A station near Petrolina Pernambuco. A randomized block design was used. The yield was determined, and the roots were analyzed for starch content. The yields of the infected plants averaged 1 O% less than the healthy controls. The starch content of the roots from infected plants was 20% less than that of the healthy controls. By combining the decrease in yield and starch content, the losses attributed to CVMV are more than 25%. This disease is endemic over most ofthe northeast ofBrazil and the incidence in the field is often very high, therefore it appears that the economic ímportance is much higher than previous estimates."},{"index":7,"size":63,"text":"The challenge is to educate the farmers in the region of the losses that they are incurring from this invisible pathogen. The introduction of health planting material is one method that the farmer can rapidly adopt to mitigate losses. This actívity needs to be combíned with rapid multiplication technologies that deliver improved varieties that can be tested for suitability using farmer participatory methods."}]},{"head":"Cassava frogskin disease (CFSD)","index":36,"paragraphs":[{"index":1,"size":8,"text":"Extent of CFSD in the northeast of Brazil."},{"index":2,"size":70,"text":"During the course of this project, cassava producers started reporting a new disease of their plants that was very severe. The roots did not expand and lip-shaped fissures appeared on the cortex of the roots. This disease has been confirmed to be cassava frogskin disease. This disease is known to be widespread throughout the Amazonian region ofBrazil, and this is the first report of the disease in the northeast ofBrazil."},{"index":3,"size":6,"text":"Analysis of the signs of CFSD."},{"index":4,"size":69,"text":"Cytological studies of the roots of normal and CFSD-affected roots were made using both light and electron microscopes. There were dramatic differences in the root periderm and cortex in the accumulation of starch. In CFSD-affected roots, the starch granules were either absent or apparently empty. The celllayers were much more densely packed in the CFSD-affected roots, and this is due to the absence of starch granules and the hyperplasia."},{"index":5,"size":65,"text":"The other characteristic ofCFSD is the enlarged lip-shaped fissures on the surface ofthe roots. These studies suggest that these fissures are caused by a hyperplasia of the cells in the root cortex. The root cortex is much thicker than normal, yet there are no starch granules in these cells. The hyperplasia is not equal aii along the cambium meristem, thus causing the lip-shaped fissures ."},{"index":6,"size":131,"text":"These studies were made to identify characteristics that can be used in screening for resistance to cassava frogskin disease (CFSD). The problem with using just root weight is that there is a high degree of variability within the cassava core germplasm collection because sorne of the materials are better adapted than others to the growing conditions in Cauca, Colombia. 1t is important to be able to distinguish between peor root growth due to peor adaptation to the growing conditions as compared to the affects caused by CFSD. This assay using the light micro seo pe is relatively rapid and inexpensive and can determine if the starch accumulation and cytology of the cells is abnormal. This assay will be u sed in the screening of the core collection for tolerance to CFSD."},{"index":7,"size":12,"text":"Screening the core collection for resistance or tolerance to cassava frogskin virus."},{"index":8,"size":42,"text":"During 1995, a field experiment was begun to analyze the 630 accessions ofthe cassava core germplasm collection for tolerance or resistance to cassava frogskin virus (CFSV). The methodology is to inoculate plants of the core collection using a single source of CFSV."},{"index":9,"size":112,"text":"Characteristics including yield and starch accumulation will be analyzed and compared with CFSD-free accessions. Over 500 of these accessions are curren ti y in the field in either the first or second cycle of evaluation. Most of the remaining accessions ha ve been inoculated and will be planted during this season. The number of infected plants per accession will be increased and screened over severa! years. The most promising clones will be tested in multilocational trials. This is a continuing activity that will take at least three to five years to get reliable results. Any resistant or tolerant accessions will be used as parents in the development of resistant germplasm gene pools."}]},{"head":"Control Strategies.","index":37,"paragraphs":[{"index":1,"size":72,"text":"Until resistant germplasm is available, the use of health planting material is the best method to mitigate losses dueto CFSD. This can be combined with the control strategy for CVMV (cassava mosaic virus) and is also useful in controlling root rots. The next phase ofthe project needs to develop a strategy of getting the farmers to produce health cassava stem cuttings to replant their fields and to trade with the adjacent comrnunities."}]},{"head":"African cassava mosaic disease epidemic in Uganda.","index":38,"paragraphs":[{"index":1,"size":74,"text":"Mrican cassava mosaic virus (ACMV) serotype \"A\" is endemic throughout Uganda and causes substantial, albeit manageable, yield losses. Since 1990, there has been a severe epidemic of African cassava mosaic disease (ACMD) that has moved from the northern regions ofUganda towards the south at the rate of 10-20 km per year. The symptoms in the plants after the epidemic arrives at a site are very severe, with the leaves becoming extreme small and deformed."},{"index":2,"size":44,"text":"When infected stem cuttings are used in the following planting cycle, the plants produce roots of no value, causing yield losses of nearly 100%. This epidemic has caused nearly a 50% decrease in total production throughout Uganda and totalloss of production in many regions."},{"index":3,"size":99,"text":"In collaboration with liT A, SCRI (Scottish Crop and research Institute, Dundee) and NARO (Uganda NAR), the molecular analysis ofthe \"A\" component ofthe severe Ugandan isolate was made. This represents 50% ofthe genome ofthe geminivirus, and the result is that the Uganda isolate appears to be a hybrid between ACMV (serotype A) and East Mrica cassava mosaic virus (EACMV, serotype B). The coat protein ofthis isolate is almost identical to ACMV and cannot be distinguished from ACMV using the currently available monoclonal antibodies specific to serotype A. The common region and the replicase gene are more similar to EACMV."},{"index":4,"size":155,"text":"Sin ce there is su eh severe deformity of the lea ves, the whiteflies m ove from severely infected plants to cassava that is not yet affected by the severe strain of ACMD in a epidemic front. When this front moved through the NARO experiment station near Kampala, sorne NAROIIITA cassava varieties showed a fair degree of resistance or tolerance to the Ugandan geminivirus. Many of these varieties are high in cyanide, anfl, while they are good for making gari, they are not suitable for the Ugandan market where fresh cassava is eaten. Breeding efforts by liTA and NARO are addressing this problem to produce resistant varieties that are low in cyanide. The fact that the epidemic is ca u sed by a distinct geminivirus, and not by simply higher levels of whiteflies, confirms the policy ofNARO to insist that only varieties resistant to the virus are replanted in the areas behind the epidemic front."},{"index":5,"size":17,"text":"4.5 Crop management, by Mabrouk El-Sharkawy, Luis Fernando Cadavid, Sara Mejía de Tafur, and Manuel Gerardo Cayón"},{"index":6,"size":233,"text":"Long-term response of cassava to NPK levels in acid infertile soils at Santander de Quilichao Table 4.5.1 contains data on the long-term response (13th year) to nitrogen-phosphoruspotassium (NPK) fertilizer in infertile acid soils at Santander de Quilichao, Cauca, Colombia. In absence ofNPK fertilizer application, dry root yield and top (aerial plant parts) biomass were significantly lower in both cassava clones (M Col 1684 and CM 91-3). After 13 consecutive cropping cycles in this soil, dry root yield was about only 4 t/ha. With application of 1 00 kglha each ofNPK, root yields were dramatically increased (about 10 t dry root/ha). The largest observed response was for K as indicated by m u eh lower yields in absence of K application and with 100 kglha ofN and P. Lesser yield responses were observed for N and P. These findings again demonstrate that K is the most limiting nutrient in these soils, which have high organic matter content (ca. 7%). To sustain reasonable productivity, K fertilizer must be applied annually since most K uptake (> 60%) is removed in the harvested roots . Long-term effects of surface mulch, fertilizer and tillage on cassava productivity in poor sandy soil in northern Colombia Table 4.5.2 presents data on root yield and plant top biomass as affected by plant surface mulch ( dry grass ), NPK fertilizer and type of tillage on sandy soils at Media Luna, northern"},{"index":7,"size":301,"text":"Colombia. Both dry root yield and top biomass were significantly increased by the application of either mulch or NPK fertilizer at a moderate leve!. On the other hand, conventional tillage increased yield only with NPK application in absence of mulch. T he combination of surface mulch and zero tillage gave the highest root yield with and without fertilizer. These findings indicate that consecutive cultivation of cassava in these poor soils would lead to very low yields unless appropriate measures are followed to maintain soil fertility . The choice between application ofNPK fertilizer or surface plant mulch would depend on various factors related to the socio-economic conditions of the local farmers . However, the potential economic return due to fertilization is high in this case. Moreover, the application of fertilizer would ensure enough quantity of planting material with high quality. Table 4.5.3 contains data on the response of cassava to both plant rnulch and NPK fertilizer in the soils of Santander de Quilichao. Although these soils contain greater organic rnatter than the sandy soils of northern Colombia, rnulch application increased root yield even in the first year of the tri al. Again, these findings indicate the beneficia! effect of plant residues as rnulch. F ertilizer application also increased root yield in these soils which have been under cassava cultivation for several years. Both plant top biornass and root dry matter content were also enhanced by applications of surface mulch and NPK fertilizer. When native weeds were repeatedly cut, without uprooting, and used for mulch, yields were depressed in absence ofNPK fertilizer. This finding suggests that weeds significantly compete for nutrients in this case. Previous research (Cassava Program Annual Reports, 1987-I 992) indicated that using post-emergence herbicides at an advanced stage of weed growth enhanced cassava productivity as compared with no weed mulch. "},{"index":8,"size":4,"text":"2.65 1.06 2.9 1"},{"index":9,"size":42,"text":"1 Fertilized with 500 kg/ha 10-20-20 NPK (50 N; 44 P; 83 K kg!ha).   (Fig. 4.5.1) was similar in both the control and the water-stressed crops, irrespective ofthe origin of the planting material. Apparently, the stake quality did not affect leaf photosynthesis."}]},{"head":"Effects of quality of planting material and water stress on cassava productivity","index":39,"paragraphs":[{"index":1,"size":75,"text":"Stomatal conductance was significantly reduced by water stress in all stake origins. However, this effect was observed only at 60 days after stress was initiated (Fig. 4.5.2). The same trend was observed in midday leafwater potential (Fig. 4.5.3). These data indicate that cassava tolerates prolonged water stress, and its lea ves maintain a high level of photosynthesis during the water stress period. Moreover, cassava conserves water by partially closing its stomata during prolonged water stress."}]},{"head":"Evaluation of crop/soil management practices in farmers fields in northern Colombia","index":40,"paragraphs":[{"index":1,"size":73,"text":"In collaboration with CORPOICA, several field trials were established in April-May 1996 in various sites to evaluate the effects of the application of mulch and fertilizer on productivity of the cassava/maize intercropping system in farmers' fields .    5 STRA TEGIC RESEARCH AT CNPMF  This study has been carried out aimed at developing an alternative method for the cassava green mite control. Preliminary results showed a decrease on survival of r urticae fed on"},{"index":2,"size":307,"text":"The conidial production of six isolates multiplied in vivo, under laboratory conditions, in May, 199 5 andin March, 1996 was evaluated in November, 1996. The results showed that the isolates 20, 22 and 23 produced a higher number of conidia when stored up to 8 months than when the storage period was 18 months. On the other hand, no effect of storage period was observed in isolates 4,15,and 21 (Table 5. 1.6). Dueto indications of storage effect on Neozygites sp. isolates, a study was carried out in order to evaluate severa! storage conditions on the viability oftwo isolates ofthe pathogen, one from Piritiba and the other from Cruz das Almas. Treatments were as follows : -1 0°C, 4°C/5% relative humidity (RH), 4°C/21% RH, 4°C/37% RH, 25°C/SO% RH . Relative humidity levels of 5%, 21% and 50%, were obtained by using glycerol solutions, while 3 7% correspond to the RH inside a refrigerator. As shown in Figure 5. l . 1, both isolates lost their viability after one month of storage period at 25°C/50% RH. The isolate from Piritiba showed no significant difference related to sporulation after eight month storage period except for 4°C/21% RH storage conditions. On the other hand, the isolate from Cruz das Almas showed no effect of storage period on sporulation when stored under -1 0°C. It is interesting to call the attention for the fact that there was no decrease in sporulation ofboth isolates, stored under -1 0°C, after the eight-month storage period, thus indicating that freezing mummyfied mites seems to be a very good storage condition, while under 25°C/50% RH the pathogen viability decreased rapidly. This is a very interesting observation since 25°C and 50% re1ative humidity are not uncommon environmentaJ conditions in cassava growing areas ofNortheast Brazil.  RH was chosen to be used in further studies of selecting Neozygites sp. isolates."},{"index":3,"size":127,"text":"Exploratory experiments, regarding the selection of Neozygites sp. isolates, consisted in evaluating conidial production of 12 isolates at 24°C and l 00% RH, to be la ter compared with results obtained at 24°C and 95% or less RH. Although significant differences were detected among isolates, a high variation in conidial production by mummies of the same isolate was al so observed, as evidenced by the standard deviation (Table 5. l . 7). Such a variation may be due to the fact that the mummyfied mites had been stored for 18 months befo re using in the experiment. Isolates stored for shorter period of time will be used in further studies of selecting Neozygites sp. isolates .    Another parameter used in studies of phenotypic characterization of Neozygites sp."},{"index":4,"size":75,"text":"isolates was the pathogen specificity. Nineteen isolates were evaluated for pathogenicity to M tanajoa and T urticae. The results showed that the isolates from T urticae, collected in Cali, Colombia, and in Jaguariuna, S tate of Sao Paulo, Brazil, were pathogenic to both T urticae and M tanajoa; on the other hand, the isolates from M. tanajoa, collected in Brazil, were pathogenic only to M tanajoa, thus showing a very high specificity (Table 5.1.8).  Figure    "}]},{"head":"Biological and economical effects of exotic parasitoids","index":41,"paragraphs":[{"index":1,"size":37,"text":"Studies on biological and eco no mica! effects of introduced parasitoids for the cassava mealybug control started by October, 1996. Data have been collected every two weeks and results will be presented in the 1997 Annual Report."}]},{"head":"Hyperparasitism","index":42,"paragraphs":[{"index":1,"size":71,"text":"After releasing the exotic parasitoids, A. diversicornis, A. coccois, and A. vexans, a significant increase of hyperparasitoid populations, mainly Pachyneuron sp. and Prochiloneurus sp, was observed. These hyperparasitoids have been able to reduce the parasitoid populations when they reach high levels under field conditions.   During the 1995/1996 growing season a very drastic drought occurred in Itaberaba and, due to that, the cover crop experiment installed in that ecosystem was completely lost."},{"index":2,"size":10,"text":"Effect of bagana mulching on cassava yield and weed control."}]},{"head":"By Genário Marcolino de Queiroz","index":43,"paragraphs":[{"index":1,"size":58,"text":"This study aims at determining the lowest amount ofbaganalha able to increase significantly the cassava root yíeld, to maintain soil moisture, and to reduce weeding frequency over the cycle of the cassava ero p. In order to reach these objectives, experiments ha ve been carried out in the cassava growing areas of Acaraú and Russas, State of Ceará."},{"index":2,"size":46,"text":"On farm trials installed in Acaraú showed that adding bagana at 180 m 3 /ha, or more, increased significantly the cassava root yield (25 .05 ton/ha) in comparison with the treatments with bagana at 45m 3 /ha (10.49 ton/ha) and without bagana (8. 11) (Tab1e 5.3.5)."},{"index":3,"size":86,"text":"Regarding weed ineidenee in the eassava field with bagana treatment, a predominanee of weeds was able to sprout out of the roots, sueh as \"Catanduba\" ( around 90% ), \"Cipauba\", \"Catingueira\" and \"Cipó-pau\" (about 10%). The cassava witches' broom disease (CWBD), caused by a phytoplasm, is a very serious cassava problem in the \"Serrada Ibiapaba\", State ofCeará, growing area. An important achievement on the research of CWBD was the observation that \"cleaning-up\" ( elimination of infection) infected planting material of susceptible varieties enabled high root yield."},{"index":4,"size":33,"text":"Despite the effectiveness ofthe cleaning-up technique, it is only a matter oftime for the disease-free susceptible planting material to become re-infected by the CWBD pathogen under field conditions, thus requiring continuous cleaning-up procedures."}]},{"head":"Genetic control of CWBD","index":44,"paragraphs":[{"index":1,"size":73,"text":"The  Preliminary results regarding reaction of30 cassava genotypes to inoculation with Fusarium sp. showed that the average area oflesion, one week after inoculation, was very small, varying from 0.29 cm 2 up to 1.57cm 2 , while the control variety Correnteza, that shows high susceptibility to root rot pathogens under field conditions, showed only 0.45 cm 2 average area of lesion, indicating again the low virulence of Fusarium sp. to the cassava crop."},{"index":2,"size":369,"text":"Although preliminary, the pathogenicity tests perforrned up to now seern to indicate that, in Northeast Brazil, S. lignico/a rnight be a more important pathogen to the cassava crop than Fusarium sp., and P. drechsleri seems to be even more virulent than S. lignicola. Studying the effect of inoculum concentration on disease development incited by S. lignicola in stakes ofthree cassava genotypes showed that the pathogen was able to cause sorne infection even at very low concentrations such as 10 3 conidia/mL. Increasing inoculum concentration increased lesion development up to 10 5 conidia/mL. Inoculum concentration of 1 0 6 conidia/mL did not significantly increase lesion development (Figure 5.4.2.2).  The main objective of the virology activity during 1996 was to determine root yield losses due to the cassava vein mosaic virus (CVMV). An experiment to study such a kind of problem requires a large amount ofvirus-free planting material, but the PCR technique did not perform well as a diagnosis method for large numbers of plants. Due to that, the production of CVMV -specific antiserum became the main objective since this technique is reliable and more easy to perform. Severa! modifications on the CVMV purification technique, such as viral separation through polyacrylamide gel electrophoresis, were made aiming at overcoming the presence of host protein in the purified virus. Regardless of all modifications, host plant protein was still present in the \" purified\" virus preparation. It was then decided to study the CVMV host range in order to identify a host from which the virus could be successfully purified. The following plants were evaluated: Amaranthus caudatus, Capsicum annun, Cassia Land property and usage About 59% ofthe surveyed cassava growers in Northeast Brazil have land property title, and the average area for them is 12.9 her; 16.7% ofthe cassava growers, average land area around 14 her, ha ve land property document other than title; other 18 .9% own their land, 5, 7 her average area, but without property title; 17.1% ofthe surveyed growers are sharecroppers with an average land area of l. 5 her; and 3.2% are renters with 1.4 her average land area. The large arnount of cassava growers without land property title, over 40%, constitutes a big problem regarding to agricultura! credit."},{"index":3,"size":159,"text":"The average Iand area of the cassava growers surveyed in Northeast Brazil, varies from 1.9 to 72 her (Table 5.5.1). Figure 5.5.1 shows land area distribution within the surveyed population. It was found that over 53% ofthe growers have land area smaller than 5 her and for almost 70% the land area is smaller than 10 her, and only 3.6% have land area larger than  Data in Table 5.5.2 show that all surveyed cassava growers use part oftheir land, 3.9 her average area, to plant either annual or perennial corps. lt is interesting to call the attention for the land used as pasture, 29.9%, left under fallow, 29.9%, and with natural vegetation, 13 .2%, all of thern generally used for grazing. This suggest a high irnportance of grazing for the surveyed cassava growers. Lowland area 7.8 7.0 1 Total of relative participation is higher than 100 because all the cassava growers surveyed have their land occupied with several uses."}]},{"head":"Rural family","index":45,"paragraphs":[{"index":1,"size":38,"text":"Table 5.5.3 shows family composition in rural communities in Northeast Brazil where cassava is one ofthe main crops. Over 96% ofthe families are composed by parents son, and daughters, while 3.1% of them include al so other relatives."},{"index":2,"size":14,"text":"The educational level of family members in the surveyed rural communities is very low."},{"index":3,"size":51,"text":"The majority ofthe youth does/did not attend school, that results in 89.02% ofthe daughters and 80.64% ofthe sons without any school education. It was found that 57.2% ofthe parents and 76.8% ofthe fami ly members including parents did not attend school, while 23 .2% are either elementary or high school educated."},{"index":4,"size":45,"text":"The head ofthe family is predominantly aman older than 18 years; 52.5% ofthem are 50 year old or less, and 70.7% are around 35 year old. Most ofthe cassava growers, 86.4%, live in the rural community while the remaining 13 .6% live in other places."},{"index":5,"size":65,"text":"Approximately one third ofthe family members, that is 35.8%, does not work in the rural community: they are either school age children or young people whose activities are other than rural labor. A little high percentage, 36.5%, work only in theír land, and 28.7%, besides workíng in their land, also sell their labor force in order to make extra money and increase the family income.  "}]},{"head":"Cassava production technology","index":46,"paragraphs":[{"index":1,"size":266,"text":"According to the recorded data, 18.9% of the cassava growers in Northeast Brazil use to hoe the area as part ofthe soil preparation activities; for most ofthe growers, 63 .7%, soi l preparation is performed only with hoe. Seventy three percent ofthe cassava growers in Northeast Brazil use stakes oftheir own to start a new planting, and 42% ofthem said they carry out any kind of stake selection prior to harvesting. The apical and basal portions of the stem are discarded and only the medium portien is used as planting material as stated by 82.9% ofthe Northeastern cassava growers; the stake must be 1 Oto 20 cm long and show a diameter higher than 2 cm according to 63 .8%. Most ofthe growers (82.6%) transpon the cassava stem as a tied up bundle, 6 1.2% plant the stake in a horizontal position, and 63 .2% of them plant in a shallow hole. If necessary, the cassava planting material may be stored for up to 60 days according to 50.5% the cassava growers, and 38.8% ofthem said that they store the planting material under a tree shade. Fertilizer and correction of soil pH by liming is nota usual practice among cassava growers in Northeast Brazil, since 65 .5% ofthem said they do not carry out these practices. For 63 .3% ofthe growers cassava planting is performed by the beginning of the raining sea son. Regarding to the topography of the area to be planted, 70% said they use flat areas, 27.5% ofthem plant in the slope area, and only 2.5% install their cassava fields in lowland areas."}]},{"head":"Pest and disease incidences","index":47,"paragraphs":[{"index":1,"size":153,"text":"As shown in Figure 5: 5.2, leaf-cutting ants (29.4%) is the most important cassava pest in Northeast Brazil, followed by root rot disease (20. 7%), horworm (16.5%), cassava green mite (13 .0%), whiteflies (8.2%), witches ' broom disease (CWBD; 3.4%), stake weevil (3 .1%), and other pests and diseases (5 .8%). Except for the cassava root rot disease that causes root infection, all the other cassava pests and diseases damage to the leaves and branches as shown in  The cassava growers' action to solve these problems are presented in Table 5.5.5. The data show that cassava growers in Northeast Brazil do not apply any control measure for CGM, termites, whiteflies, stake weevil nor witches' broom disease. On the other hand, attempts to control cassava pests by growers has been based on insecticide application. For cassava root rot disease, growers have been using lime and ash as soil amendment aiming at controlling the disease."}]},{"head":"Commercialization","index":48,"paragraphs":[{"index":1,"size":134,"text":"Looking at the source of information from where the surveyed growers know about prices of cassava products, it was found that, for cassava flour, starch and fresh root, the information comes from the local market, while for cassava chips the information comes from the extension personnel (Table 5.5.6). The majority ofthe cassava production in the Northeast, 76.8%, is soldas cassava flour, 19 .1% is soldas fresh root, 1.6% is used as animal feeding, and only 0.7% is transformed to chips (Table 5.5.7). Regarding the manner of commercialization, 21.17% ofthe cassava flour, 0.05% of \"tapioca\", and 1.03% ofthe starch products are sold to wholesalers; 0.37% ofthe \"beiju\" production is sold directly to the consumer; 0 .37% ofthe chips is commercialized through growers associations; and 5.85% ofthe root production is sold to truck drivers (Table 5.5.8).  "}]}],"figures":[{"text":" liT A is eager to release the fungal pathogen Neozygites c. f jloridana in Africa to help "},{"text":"Farmer participatory research. The final training course \"Participatory Methods for Evaluation ofTechnology Trials with Farmers\" held at CNPMF/EMBRAPA in April was attended by 30 researchers and extension workers, representing 6 collaborating research and technology transfer institutions in_the states ofBahia, Ceará, Pernambuco and Paraiba, Brazil. "},{"text":"Formation ofa second generation ofCOPALs (farmer research comrnittees) was initiated during 1996 in the S tate of Ceará through a project presented by local institutions to the Banco do Nordeste do Brasil (BNB). This project financed the establishment of COP ALs in six communities of cassava growers that had been identified during the participatory survey carried out by PROFISMA in 1994. Financia] support received from BNB included seed money to start the first COP AL FPR experiments, funds for farmer training events and for fue! and per diems for technicians assisting the COP AL. The COP ALs were autonomously organized by local institutions followed the same methodology taught by PROFISMA. Field days were held in Ceará and Pernambuco in 1996 with the aim of stimulating more support for COP AL activities at local and state level. The COP AL methodology for enhancing fanner participation in research and technology transfer activities and the initial FPR results obtained by PROFISMA were presented to 160 fanners, technicians and decisionmakers. PROSERTÁO is a rural development project executed by the Government ofthe State of Sergipe, Northeast Brazil, with financial support from IF AD through a 25 million dollars loan during a seven years period. PRQSERT ÁO staff approached CNPMF looking for technical assistance to sol ve the problem of root rots which plagues 95% of the municipalities in the project area. Ajoint proposal was developed in which PROSERTÁO funds activities by CNPMF that include: 1) the implementation of a training program in FPR & COP AL methodology for PRO SER T ÁO personnel, 2) establishment of COP ALs in sorne selected cassava growing areas, and 3) execution of fanner participatory activities to develop and transfer technologies to control cassava root rot. "},{"text":"First experiences and results obtained by PROFISMA about the use of participatory methods for evaluation of technology trials with farmers are very encouraging. The technicians in volved, despite the fact that they are in most of the cases new practitioners, have been able to adapt the methods to their own conditions and have stimulated farmers to make their own evaluations. Conversely, the farmer members of the COP ALs and the other fanners that collaborated with them managed to produce their own evaluation results and made a very important step forward in the process ofbuilding local, community level capacity to participate actively in technology generation and transfer activities. Another very important result of these activities was the strengthening of the collaborative relation between the technicians and the COP ALs. "},{"text":" and had previously been identified through farmer participatory selection conducted in a germplasm development project financed by IFAD. The other two were selected by farmers from among the best locally produced material. The experiment was planted in randomized blocks with three repetitions. Planting distances were 1. O by 1. O m. One of the introduced varieties performed better than the local ones(Figure 3.2.1.4). The best introduced material produced 19% more roots yield than the best local variety. Two ofthe introduced materials showed lower dry matter (poorer quality) content than the local varieties, a factor to be considered in future breeding work. Farmers' preference ranking evaluation was not consistent with the agronomic data. They selected as the best two treatments the two local varieties (Platina and Jalé) that gave lower yields than the two best introduced materials (Maria Pau 118 and 128/08).F armers ranked three of the introduced materials as worse options although one of them, Maria Pau 118, was the most productive (Figure3.2. 1.4). The results were discussed with the COPAL and with other farmers ofthe community, and the planning of the second experiment resulted in the inclusion of these two promising clones, the introduction from CNPMF of two new ones and the inclusion of the two best local varieties as the check treatment.Members of this COP AL al so participated in training activities for evaluation of cassava green mite damage. The results oftheir evaluations are presented in Figure3.2.1.5. It can be observed that Jalé, the preferred local variety did show the best resistance to cassava mites, justifying its local popularity. Three of the four varieties introduced from CNP\"MF showed medium tolerance to mite damage, but two ofthem (Osso Duro and 47/ 19) gave the lowest yields ofthe experiment. The other variety, Maria Pau 118, was the most productive, and although it was ranked very poorly by farmers, it showed them the possibility of adapting it to their cassava systems since it produced 19% more that their local best variety. "},{"text":"Figure 3 Figure 3.2.1.5. Evaluation of cassava green mite damage at Buril, Crisópolis, Babia. "},{"text":" They are now starting to question the economic viability of this practice. Building up in this initial experience, the COP AL has already planted a second experiment in which sorne improved varieties recommended by CNPMF were introduced.COP AL: Barra, Sáo Miguel das Matas, Babia Cassava farmers in this cornmunity diagnosed whiteflies (Aleurothrixus aepim) as the main constraint to cassava cultivation in the region. The objective of the experiment designed with this COP AL was to evaluate five cassava varieties for whitefly resistance/tolerance. Three of the varieties planted were introduced from CNPMF germplasm bank and were recommended for testing by the COP AL based on excellent results obtained in other experiments in similar semi-arid ecosystems. These three clones were also selected as promising varieties by farmer groups involved in another farmer participatory research project being executed by CNPMF and CIAT in Northeast Brazil. The other two varieties were selected by the farmers as their best locally available options. The experimental design was complete randomized blocks with five repetitions (five different farmer fields located within a distance of about 1 km). Although the main objective of the experiment could not be addressed to a great extent due to the absence of a severe attack of whiteflies during the experiment, the results obtained allowed farmer members ofthe COPAL, other farmers ofthe community and technicians sorne important initial conclusions. "},{"text":"Figure 3 Figure 3.2.1.6. Evaluation of fertilization methods on yields of two cassava varieties at COPAL Cadete, Cruz das Almas, Bahia. "},{"text":"Figure 3 Figure 3.2.1.8. Evaluation of cassava planting systems (double row, single row and legumes intercropping) at Umbuzeiro, Anguera, Babia. "},{"text":"53 Fig. 4.1. 1 shows the distribution of 685 sites explored for mite predators of cassava green mite in Latin America by CIA T and EMBRAP A. "},{"text":"Figure 4 . Figure 4.1.1. Sites in Latín America sampled for predators of cassava green mite. "},{"text":"Figure 4 Figure 4.1.2. Sample sites in Zambia that served as the target for generating principal component analysis of climate (N=52). "},{"text":"Figure 4 . Figure 4.1.3. Climate ofZambian target region, based on 52 sample sites (precipitation, temperature, diurnal temperature range). "},{"text":"Figure 4 . Figure 4.1.4. • Map of climatic similarity to target sites in Zambia used to identify bigb priority regions in tbe Brazilian central bigblands and Mexico for predator exploration. "},{"text":"Figure 4 Figure 4.1.5. Effect of different food sources on female adult longevity of several species of predatory phytoseiid mites. "},{"text":"Figure 4 . Figure 4.1.6. Effect of different food sources on fecundity of several species of predatory phytoseiid mites. "},{"text":"Figure 4 Figure 4.1. 7. Pathogenicity of five strains of Neozygites c.f. jloridana on 3 species of tetranychid mites associated with cassava (mt-from M tanajoa; tu-from T.urticae; af-from Benin, Africa; cd -from Cruz das Almas, Babia, Brazil; mi -from Media Luna, Magdalena, Colombia; ct-from CIAT, Valle de Cauca, Colombia). "},{"text":"Figure 4 Figure 4.1.8. Proportion of samples containing individuals infected by Neozygites sp. (as indicated by the presence of hyphal bodies) in the 11 most common species of tetranychid mites in the CIA T collection (+ , higher than expected; -, lower than expected; chi-square test with standardized deviations greater than 2). "},{"text":"Figure 4 Figure 4 Figure 4.1.9. In vitro multiplication of a Neozygites cf.jloridana strain isolated from T. urticae (TuCIATl) with and without antibiotics (streptomycine + tetracycline) in two difTerent tissue culture media (T, TNMFH + lactalbumin + yeastolate; TS, TNMFH + lactalbumine + yeastolate + fetal bovine serum). "},{"text":"( Fig. 4.1.12a). Those initiated with 200 females fluctuated from week to week the most, suggesting possible crowding effects. Production of adult female T. tenuiscutus in the Mesa-Bellotti mass-rearing system per number of females used to initiate the culture was highest at the lowest density tested (50 females; Fig.4 .1.12b)  suggesting the effect of competitive interactions at the higher densities. "},{"text":"Figure 4 . Figure 4.1.11. Effect of initial number of T. tenuiscutus females used to establish Mesa-Bellotti mass-rearing cultures on the number of adult female progeny harvested. "},{"text":"Figure 4 . Figure 4.1.12. Production of female T. tenuiscutus in the Mesa-Bellotti mass-rearing system: A) number of adult females harvested per container, B) number of adult females harvested per initial female per container. "},{"text":"Figure 4 .Figure 4 Figure 4.1.13. Diagram of stage-structured computer simulation model to help optimize mass-rearing of phytoseiid mites. "},{"text":" sp. \"b\" was the seeond most numerous parasitoid eolleeted, eomprising 16.9% of all the individuals collected. The two speeies E. hispida and Eretmocerus sp. \"b\" were the most widely distributed throughout the three regions surveyed. They were the most abundant speeies in the Llanos with 79.3% and 69. 1 %, respeetively. In the Andean zone they represented 20% and 24%, respeetively. Sorne whitefly host speeifieity for the different speeies of parasitoid was also noted. A. spiniferus was only obtained from A. socialis; E. hispida and Eretmocerus sp. \"b\" were only colleeted from A. socialis in the North Coast and the Llanos, and it highly preferred A. socialis in the Andean zone. Parasitoid speeies obtained from B. tuberculata were rare in all three regions. Eretmocerus sp. \"e\" was the most frequent speeies found on B. tuberculata in the Andean Zone. "},{"text":"4. 3 . 1 Figure 4.3.1. "},{"text":" Filtrates from liquid cultures of Trichoderma isolate 11 TSM-4 caused marked reduction in growth ofthe pathogen D. manihotis after 24 h ofincubation. Filtrates of 14PDA-4 were most effective in reducing the growth ofF. oxysporom. The culture filtrates ofthis Trichoderma spp. isolate caused 40% growth inhibition of the pathogen. They were toxic in each replication until the end of the experimentation period of 1 week. Experiments are ongoing to study the effect of isolates on pathogen spore germination and germ tube elongation, and the effect of application of pure and mixed extracts of these isolates on infected cassava plants. Evaluation of Pseudomonas spp. by excised shoot bioassay Biocontrol strains from the genera Pseudomonas were tested for antifungal activity in bioassays in vitro. This study is undertaken to select strains to control Phytophthora spp. Shoots of cassava cultivar CG 1-3 7 in an excised shoot bioassay were bacterized, and 3 d la ter inoculated by a Phytophthora spp. suspension. Prelirninary observations indicate that from 9 isolates, 1 antagonist inhibited lesion development of the cassava sprouts. "},{"text":"Figures 4 . Figures 4.5. 1, 4.5.2 and 4 .5.3, present  data on leafphotosynthesis, stomatal conductance and midday leaf water potential as affected by stake quality and water stress. In this tri al, planting material ofM Col 1684 were obtained from the long-term NPK trial at Quilichao on the 12th cropping cycle. Mother plants with the following NPK levels were used: O, O, O (TI); 50, 50, 50 (T2); 100, 100, 100 (T3); and 100, 100, O (T4) kg/ha N, P, K. The trial was conducted in the field lysimeter at Quilichao, where half of the experimental area was deprived of water at 65 days of planting by covering the ground with plastic sheets for 3 months. Leaf net photosynthetic rate "},{"text":" These trials are located in Los Palmitos, Dept. of Sucre; in Plato, Dept. of Magdalena; Pueblo Nueva, Dept. of Cordobá; Pivijay, Dept. of Magdalena; Chiriguana, Department ofCésar; and in El Carmen de Bolívar, Dept. ofBolivar. These trials will be harvested in Feb./March 1977. In addition to the research mentioned above, the Associate, Luis F. Cadavid, had participated in two training workshops for specialists of CORPOICA in regions 2 and 3. He prepared and dictated two courses on integrated crop/soil management. The first course was in Barranquilla, Atlantico in May 1996, and the second was in Turipana, Montería, Cordobá in August 1996. "},{"text":"Figure 4 . Figure 4.5.1 Effects of the quality of planting material and water stress on leaf photosynthesis. Arrow, Initiation of stress. Stakes were obtained from mother plants on the l3 1 h cycle of a long-term NPK trial that received annually the following treatments: T 1 =0,0,0 NPK; T 2 =50,50,50 kg!ha NPK; T 3 ;;:100,100,100, kg/ha NPK; T 4 =100,100,0 kg!ha NPK. (bars, ±sd). "},{"text":"Figure 4 Figure 4.5.2 Effects of the quality of planting material and water stress on leaf conductance. Arrow, initiation of stress. Stakes were obtained from mother plants on the l3 1 h cycle of a long-term NPK trial that received annually the following treatments: T 1 =0,0,0 NPK; T 2 =50,50,50 kglha NPK; T 3 = 100,100,100, kglha NPK; T4= 100,100,0 kglha NPK. (bars, ±sd). "},{"text":"Figure 4 . Figure 4.5.3 Effects of the quality of planting material and water stress on midday leaf water potencial. Arrow, initiation of stress. Stakes were obtained from mother plants on the 13'h cycle of a long-term NPK trial that received annually the following treatments: T 1 =0,0,0 NPK; T 2 =50,50,50 kg!ha NPK; T 3 = 100,100,100, kglha NPK; T 4 =100,100,0 kg!ha NPK. (bars, ±sd). "},{"text":" Figure 5.1.2. Effect of humidity levels on conidial production of two Neozygites sp.isolates. "},{"text":" installed in May, 1996 in Piritiba, Bahia, with the objective of evaluating the efficiency of field inoculation of Neozygites sp. to control CGM. Ten inoculations were performed from May 22 to June 24, using 40 mummyfied mites as source of inoculum. Dispersion was evaluated by both visual detection of infected mites and by using spore traps; final evaluation was carried out early August. Very low levels of Neozygites sp. infected mites were observed from May to August. The pathogen was found in five evaluations in the inoculated area and only once in the control (Figure5. 1.3). The first infected mites were observed by July 14 in the control f1eld while in the inoculated area the pathogen was detected by July 17, that is 23 days after the last field inoculation (Figure5.1.3). It is irnportant to call attention to the fact that the CGM population was low, around 25 individuals/leaf, over all the evaluation period. Infected rnites were found up to 45 m away frorn the inoculation site, and by August 2, the pathogen had spread all over the field . These results do not allow ruling out the efficiency of field inoculations with Neozygites sp. to control CGM. The nurnber of rnurnrnyfied rnites used as source of inoculurn seerns to be low. Methodological adjustrnents will be rnade in order to overcorne this problern in "},{"text":"Figure 5 Figure 5.4.2.1. Reaction of three cassava genotypes to stake inoculation with Fusarium sp. and Scytalidium lignico/a. "},{"text":"Figure 5 Figure 5 Figure 5.4.2.2. Effect of inoculum concentration of Scytalidium lignicola, on disease development of three cassava genotypes. "},{"text":" 137 "},{"text":" occidentalis, Canavalia ensiformis, Chenopodium amaranticolor, e mura/e, e quinoa. Citrullus vulgaris, Cucumis anguria, e me/o, Gossypium hirsutum, He/iantus annun, Lactuca saliva, Lycopersicum escu/entum, Nicotiana benthaminana, N rustica, N glutinosa, N tabacum, Sesamum orienta/e and Manihot escu/enta. Severa! inoculation techniques were tested, including injection of purified virus into plant tissue, and grafting. Syrnptorn development was observed only i_ n cassava plants inoculated by grafting. This study will continue by evaluating other potential host plants. 5.5 CASSA VA INTENSIVE DIAGNOSTIC SURVEY IN NORTHEAST BRAZIL, by Jose Hurnberto Almeida de Cerqueira and Carlos Estevao Leite Cardoso "},{"text":"139Figure 5 Figure 5.5.1. Distribution of average land area of cassava growers in Northeast Brazil. "},{"text":" !~.~-~. tr .. ~~~P..~.~~~~-~~---•- "},{"text":"Table of Contents \"Ecologically Sustainable Cassava Plant Protection in South America and Africa: An Environmentally Sound Approach\" Technical Report on Activities conducted during 1996 by PROFISMA (Prot~io Fitossanitária Sustentavel da Mandioca): the South American (Prot~io Fitossanitária Sustentavel da Mandioca): the South American component of a global UNDP project component of a global UNDP project Project Ref. GL0/91/013 Project Ref. GL0/91/013  "},{"text":" After careful weighing of the altematives, the CIAT coordinator in Brazil decided to eliminate his own position, as well as sorne junior staffpositions in Brazil and at CIAT. Nigeria field sites) and the other toured ESCaPP/Benin field sites during the first 4 days ofthe review. The groups reunited in Cotonou for 2 days of presentations.ESCaPP presented impressive achievements. A large number of national program scientists and extensionists have been trained in production methods, and these, using local extensionists as multipliers, have ~stablished on-farm trials with grower participation. We visited severa! of these in Benin. The National Coordinator for ESCaPP in Benin, Norbert Maroya, was particularly impressive -organized, articulate, in touch with field activities and obviously motivated and comrnitted to the project. Overall, we were impressed with the enthusiasm and commitment of national program staff to the project -a marked contrast with 2 PROJECT COORDINATION 2 PROJECT COORDINATION 2.1 Coordination at CIA T, by Steven Lapointe 2.1Coordination at CIA T, by Steven Lapointe  The uncertainty of continued funding of this very successful project caused major The uncertainty of continued funding of this very successful project caused major disruption during 1996 and resulted in considerable effort directed to a search for continued disruption during 1996 and resulted in considerable effort directed to a search for continued support. The one-year extension provided by UNDP for 1997, while considerable and support. The one-year extension provided by UNDP for 1997, while considerable and generous, given the current financial status ofthat agency, was insufficient to maintain all generous, given the current financial status ofthat agency, was insufficient to maintain all activities. This resulted in enough savings to allow retention of most project junior staff and the activities. This resulted in enough savings to allow retention of most project junior staff and the continuation of essential activities through 1997. continuation of essential activities through 1997.  African proposal concepts. The training component ofPROFISMA Phase 2 was prepared by African proposal concepts. The training component ofPROFISMA Phase 2 was prepared by  CNPMF in collaboration with IPRA (CIAT program on farmer participatory research) CNPMF in collaboration with IPRA (CIAT program on farmer participatory research) personnel and was sent to the Chairman of the EMBRAP A Intemational Cooperation Extemal Advisory Committee (EAC) Review personnel and was sent to the Chairman of the EMBRAP A Intemational Cooperation Extemal Advisory Committee (EAC) Review  Department. The second and final extemal review of the African activities (ESCaPP project; Department. The second and final extemal review of the African activities (ESCaPP project; Ecologically Sustaínable Cassava Plant Protection) took place during June, 1996 in Benin and Ecologically Sustaínable Cassava Plant Protection) took place during June, 1996 in Benin and Nigeria. The three Extemal Advisory Committee (EAC) members that reviewed PROFISMA Nigeria. The three Extemal Advisory Committee (EAC) members that reviewed PROFISMA in Cali in August 1995 (John Borden, Don Roberts, Asuncion Raymundo) were joined by Dr. in Cali in August 1995 (John Borden, Don Roberts, Asuncion Raymundo) were joined by Dr. Mohamed Dahniya. Bernardo Ospina (farmer participatory research trainer) and Steve Mohamed Dahniya. Bernardo Ospina (farmer participatory research trainer) and Steve  "},{"text":" He stressed the interdisciplinary characteristics of our activities since a Weed Scientist, Entomologists, Plant Pathologists, Agronomists, Soil Scientists anda Plant Taxonomist are working together. His main suggestions for future actions were: i) survey of pathogens on weeds~ ü) take also into consideration, besides the relative importance, the index of importance value, when discussing recorded data~ iü) develop basic studies on nutrient uptake by weeds, weed response to mineral and organic fertilizers, and weed response to drought and nutritional stress.By early December, 1996, the Coordinator of Agricultura! Development ofPROSERTAO (an IFAD-funded development project in Sergipe), together with 13 extension workers from that project, visited EMBRAP A/CNPMF in arder to maintain contact with the coordinators of PROFISMA and the IF AD-funded project conducted by EMBRAP A/CNPMF. He expressed an interest in visiting a COP AL in arder to observe in situ how the COP AL methodology has been implemented among cassavagrowers. The PROSERTAO team visited the COPAL Colonia, located in lnhambupe, State ofBahia and was favorably impressed. second concept note entitled, \"Ecologically Sustainable Cassava Plant Protection: A Global Strategy\" was written jointly by CIA T and ITT A in July to unify the Latin American and Afiican proposal concepts. This concept note was sent to UNDP for consideration of possible funding of a second phas~ of the PROFISMAJESCaPP project beginning in 1997.  20 20 2.2 Coordination at EMBRAPA/CNPMF, by Aristoteles Pires de Matos 2.2Coordination at EMBRAPA/CNPMF, by Aristoteles Pires de Matos 3. Established 30 Local Agricultural Research Committees (COPALs) in 4 states of PROFISMA computer database 3. Established 30 Local Agricultural Research Committees (COPALs) in 4 states of PROFISMA computer database Northeast Brazil. A computer database called Participatory Research System (SPP AR), is currently in the Northeast Brazil. A computer database called Participatory Research System (SPP AR), is currently in the final elaboration phase. Data from one rural community has already been entered to test it. America in Northeast Brazil for control ofthe cassava green mite (CGM). Establishment is 4. These COP ALs, with support from extensionists and national program researchers, will The database runs in FOX-PROT for Windows versions 3.1 and 95, and it has image storage tentative and spread is not yet documented. Protocols for exploration, collection, shipping, quarantine, rearing and release were developed for rapid, multiple introductions of additional have planted and evaluated two cycles of experiments in their communities addressing pest and disease constraints identified by farmers. capability. The training component ofPROFISMA Phase 2 was prepared by PROFISMA' s Training final elaboration phase. Data from one rural community has already been entered to test it. America in Northeast Brazil for control ofthe cassava green mite (CGM). Establishment is 4. These COP ALs, with support from extensionists and national program researchers, will The database runs in FOX-PROT for Windows versions 3.1 and 95, and it has image storage tentative and spread is not yet documented. Protocols for exploration, collection, shipping, quarantine, rearing and release were developed for rapid, multiple introductions of additional have planted and evaluated two cycles of experiments in their communities addressing pest and disease constraints identified by farmers. capability. The training component ofPROFISMA Phase 2 was prepared by PROFISMA' s Training species of natural enemies in 1996 and 1997. Coordinator in collaboration with EMBRAP A personnel and was sent to the Chairman of the species of natural enemies in 1996 and 1997. Coordinator in collaboration with EMBRAP A personnel and was sent to the Chairman of the m. Areas of global coUaboration between llTA and CIA T Workshop on the cassava root rot disease EMBRAP A Intemational Cooperation Department. The Plant Pathology and Entomology Farmer participatory research (FPR) consultant Graduate students (Institutional Relationship) On April 8 to 11, 1996, a workshop on cassava root rot diseases was held at components ofPROFISMA Phase 2 were prepared by PROFISMNCNPMF staff, based on m. Areas of global coUaboration between llTA and CIA T Workshop on the cassava root rot disease EMBRAP A Intemational Cooperation Department. The Plant Pathology and Entomology Farmer participatory research (FPR) consultant Graduate students (Institutional Relationship) On April 8 to 11, 1996, a workshop on cassava root rot diseases was held at components ofPROFISMA Phase 2 were prepared by PROFISMNCNPMF staff, based on cassava growers' demands as identified by the participatory diagnostic surveys. These cassava growers' demands as identified by the participatory diagnostic surveys. These components will be discussed with the CNPMF cassava research team for further adjustments, components will be discussed with the CNPMF cassava research team for further adjustments, before sending to donors. before sending to donors. D. Farmer Participatory Research in NE Brazil D. Farmer Participatory Research in NE Brazil l . Completion of extensive and intensive participatory diagnostic surveys of cassava growers l . Completion of extensive and intensive participatory diagnostic surveys of cassava growers in NE Brazil. Major biotic and abiotic constraints to production in small-scale cassava in NE Brazil. Major biotic and abiotic constraints to production in small-scale cassava production systems were identified through participatory surveys that emphasized farmers' 7. Global project coordination and exchange. Weed management consultant Intemational Development (USAID), W. Alton Jones Foundation, Inc., Jessie Srnith Noyes production systems were identified through participatory surveys that emphasized farmers' 7. Global project coordination and exchange. Weed management consultant Intemational Development (USAID), W. Alton Jones Foundation, Inc., Jessie Srnith Noyes perceptions and priorities. Approximately 1,600 farmers were contacted. During 1996 Dr. Robinson Antonio Pitelli, Professor ofWeed Management, Universidade Foundation, Weeden Foundation, The Charles Stewart Mott Foundation, Andrew W . Mellan perceptions and priorities. Approximately 1,600 farmers were contacted. During 1996 Dr. Robinson Antonio Pitelli, Professor ofWeed Management, Universidade Foundation, Weeden Foundation, The Charles Stewart Mott Foundation, Andrew W . Mellan Estadual Paulista, Jaboticabal, S tate of Sao Paulo, was a consultant for the activities related Foundation, The Rockefeller Foundation, Inter-American Development Bank, Ciba-Geigy Estadual Paulista, Jaboticabal, S tate of Sao Paulo, was a consultant for the activities related Foundation, The Rockefeller Foundation, Inter-American Development Bank, Ciba-Geigy  "},{"text":"o Root yield • Dry matter 1 14.7    14.7  13.25 12.9 12.45 13.2512.912.45 Jalé Platina Osso Duro 47/19 JaléPlatina Osso Duro47/19 82 ...--- O Fanners' preference ranking 82 ...---O Fanners' preference ranking     44 44     r---- r----   16 n 16 n Jalé Platina Osso Duro 47/19 JaléPlatinaOsso Duro47/19  "},{"text":" .2.2. 1 ). COP AL is the only farmers research group supported by PROFISMA that is located in a land reform community. The group is composed by 65 families and practices collective production and processing of various crops such as cassava, coro, beans, and banana. Cassava is a very important crop for the group, which is attempting to beco me self sufficient and also uses surplus cassava flour for commercialization. The crop has been affected severely during the last few years by the mycoplasm witches' broom disease (WB) and the group has been actively involved in research work conducted by CIA T, CNPMF and local institutions aimed at finding sources of genetic resistance/tolerance to this disease.   Cassava roots yield  CVariety: Cruvela Cassava roots yieldCVariety: Cruvela 18 14 14.0    •variety: Oulho Roxo 18 1414.0•variety: Oulho Roxo 11      11 .2 10 l • ! 8 4      .2 10 l • ! 8 4 2      2 0+-....... -      0+-....... - Cassava + Cassava + Cassava + Cassava + Cassava + Cassava alone Cassava +Cassava +Cassava +Cassava +Cassava +Cassava alone pigeon pea+ compost Crotalaria + Crotalaria pigeon pea pigeon pea+compostCrotalaria +Crotalariapigeon pea compost  compost   compostcompost 6      6 5 4.6  Dry matter yield  54.6Dry matter yield ~ 4      ~ 4 !.3 ! 2      !.3 ! 2 1      1 0+-....... -      0+-....... - Cassava + Cassava + Cassava + Cassava + Cassava + Cassava alone Cassava +Cassava +Cassava +Cassava +Cassava +Cassava alone pigeon pea+ compost Crotalaria + Crotalaña pigeon pea pigeon pea+compostCrotalaria +Crotalañapigeon pea compost  compost   compostcompost   Farmers' prererence ranking  Farmers' prererence ranking    36   36 30      30 !! ~ 20      !! ~ 20 10      10 0+-....... -      0+-....... - Cassava+ Cassava+ Cassava + Cassava + Cassava + Cassava alone Cassava+Cassava+Cassava +Cassava +Cassava +Cassava alone compost An interesting aspect of the work conducted by this COP AL is that they are now utilízing compost plgeon pea+ compost Crotalaria + Crotalaria pigeon pea compost An interesting aspect of the work conducted by this COP AL is that they are now utilízing compost plgeon pea+ compost Crotalaria + Crotalaria pigeon pea their experiences and skills as \"farmer researchers\" and have installed sorne simple their experiences and skills as \"farmer researchers\" and have installed sorne simple experiments with other crops such as pepper and tomato. AdditionaJly, this COP AL is being Figure 3.2.2.1. Evaluation of cassava intercropping with pigeon pea and crotalaria in experiments with other crops such as pepper and tomato. AdditionaJly, this COP AL is being Figure 3.2.2.1. Evaluation of cassava intercropping with pigeon pea and crotalaria in double row planting with compost fertilization at Nova Veneza Ubajara, used by EMA TER CE as a demonstration, training ground in which other comrnunities are Ceara. double row planting with compost fertilization at Nova Veneza Ubajara, used by EMA TER CE as a demonstration, training ground in which other comrnunities are Ceara.  "},{"text":" The main argument to justify this experimental objective was that sweet cassava varieties are almost disappearing in the region although in past years they were very popular among farmers. The COP AL feels that there is great demand and good market opportunities for these varieties and decided to start an identificationlobservation with those materials available in the State with the aim of adapting and selecting the most appropriate ones for their ecosystem.The observation field was installed in an area closed to the community that belongs to a local University (Universidad do Vale do Acaraú). The integration with this University could be a very important support for the COP AL future technology adaptation efforts. The experiment included 21 varieties collected in different regions of the S tate. The planting system was double rows intercropped with six different legumes. These two practices were new to the group. After 15 months.the experiment was harvested, and farmers performed an evaluation of the best cultivars based on criteria such as plant development, root production and especially palatability (cooking time and softness). After this evaluation, only 10 cultivars were selected for future research work. Sorne legumes used in intercropping with the cassava were harvested and the seeds were sold to farmers in the region. This activity could be an additiona1 source of income for the farmers.4 STRATEGIC RESEARCH AT CIAT 4.1 Biological Control of Cassava Green Mite, by Lincoln SmithThe cassava green mite (CGM, Mononychellus tanajoa) is one ofthe principal pests of cassava in Africa and Northeast Braz!l._ The principal objectives ofthe CIAT acarology unit are to find natural enemies (predators or pathogens) ofCGM, evaluate them for safety and suitability as biological control agents, and send them to EMBRAP A in Brazil and liT A in Benin for release. Corollary activities include conducting research to further develop methods to evaluate natural Corollary activities include conducting research to further develop methods to evaluate natural enemies, mass rear them and release them; to publish findings and disseminate information to enemies, mass rear them and release them; to publish findings and disseminate information to national programs; and to assist Brazilian scientists and extension agents working on integrated national programs; and to assist Brazilian scientists and extension agents working on integrated pest management of CGM. pest management of CGM.  "},{"text":"Table 4 . 1.llists the colonies ofphytoseüd predatory mites maintained at CIAT for experimental evaluation. Three species of T etranychid pest mites (Mononyche/lus tanajoa, M. caribbeanae, Tetranychus urticae) were maintained to feed the predators and to use in experiments. Several species ofinseGts (thrips Corynothrips stenopterus, mealybug Phenacoccus he\"eni, whitetly Aieurotracheius socialis) and the foliar fungal plant pathogen, Oidium manihotis, were also maintained for use in feeding experiments.  "},{"text":"Table 4 . 1.1 Phytoseiid strains maintained in laboratory colonies at CIA T, 1996. Origin Date OriginDate  "},{"text":" So far, none of the irnported predatory mites ha ve beco me established in the East African plateau. We suspect that this is because this target region is too hostile to the strains that were      55 55 Climatic matching with Zambia    Climatic matching with Zambia Species Country Dept./State Municipality Location Collected SpeciesCountryDept./State MunicipalityLocationCollected Typhlodromalus VENEZUELA Yaracuy Marin San Felipe Mar-95 TyphlodromalusVENEZUELAYaracuyMarinSan FelipeMar-95 manihoti      manihoti 11 BRASIL Bahia Cruz das Almas  Feb-93 11BRASILBahiaCruz das AlmasFeb-93 11 COLOMBIA Ca u ca Cajibio  Jun-95 11COLOMBIACa u caCajibioJun-95  \" Antioquia Barbosa El Hoyo Jan-96 \"AntioquiaBarbosaEl HoyoJan-96 11 \" Antioquia Copacabana Montañita Jan-96 11\"AntioquiaCopacabanaMontañitaJan-96 11  Magdalena Medialuna  Feb-96 11Magdalena MedialunaFeb-96 11  Guajira Villanueva  Jan-96 11GuajiraVillanuevaJan-96 11 \" .. Caldas Santander Chinchiná B/manga San Gregorio Bijagual Aug-96 Aug-96 11\" ..Caldas SantanderChinchiná B/mangaSan Gregorio BijagualAug-96 Aug-96 11 .. Santander B/manga Los Colorados Aug-96 11..SantanderB/mangaLos ColoradosAug-96  \" Risaralda Sta. Rosa de Cabal UNISARC Aug-96 \"RisaraldaSta. Rosa de Cabal UNISARCAug-96  \" Quindío Armenia Armenia Aug-96 \"QuindíoArmeniaArmeniaAug-96 T aripo COLOMBIA Valle Palmira CIAT Sep-96 T aripoCOLOMBIAVallePalmiraCIATSep-96 T tenuiscutus ECUADOR Manabí Portoviejo  Nov-94 T tenuiscutusECUADORManabíPortoviejoNov-94 \" H Manabí Puerto Cayo Cantagallo Dec-95 \"HManabíPuerto CayoCantagalloDec-95 T. limonicus BRASIL Sao Paulo Jaguariuna  Jun-90 T. limonicusBRASILSao PauloJaguariunaJun-90 N. idaeus ECUADOR Manabí Rocafuerte Entrada a Danzarín Dec-95 N. idaeusECUADORManabíRocafuerteEntrada a DanzarínDec-95 N. californicus ECUADOR Manabí Portoviejo  Nov-94 N. californicusECUADORManabíPortoviejoNov-94 G. annectens ECUADOR Manabí Portoviejo Crucita/La sequita Dec-95 G. annectensECUADORManabíPortoviejoCrucita/La sequitaDec-95 G. helveolus ECUADOR Manabí Puerto Cayo Cantagallo Dec-95 G. helveolusECUADORManabíPuerto CayoCantagalloDec-95 Euseius ho ECUADOR Manabí Rocafuerte Entrada a Danzarín Dec-95 Euseius hoECUADORManabíRocafuerteEntrada a DanzarínDec-95  "},{"text":"Exportation of natural ene ... ies Exportations of natural enemies during 1996 included Typhlodromalus tenuiscutus from a dry Iocation in coastal Ecuador (Portoviejo, Manabí) which was sent to CNP.MFIEMBRAPA, Cruz das Almas, Bahia via quarantine at CNPMA, Jaguariúna, Sao Pauto Brazil (Table4. 1.2). Strains oiTyphlodromalus manihoti from severa! high altitude sites in Colombia (Barbosa, Cajibio and Copacabana, Bucaramanga, Armenia, Chinchina and Santa Rosa de Cabal) were sent to liT A,  "},{"text":"Table 4 . 1.2. Cultures of predatory pbytoseiid mites exported from CIA T in 1996. Date   Colony Number Number  o/o DateColonyNumber Numbero/o Sent Species Source Establisbed Sent Received Destination Survival SentSpeciesSourceEstablisbedSentReceived Destination Survival 3/11/96 T. tenuiscutus Portoviejo, 12/95 400 + 184 + CNPMA, 46% 3/11/96 T. tenuiscutusPortoviejo,12/95400 +184 +CNPMA,46%   Ecuador  imms. 42 eggs Brazil 1 Ecuadorimms.42 eggsBrazil 1 4/23/96 T. manihoti Barbosa, l/96 910 432 Amsterdam2 47% 4/23/96 T. manihotiBarbosa,l/96910432Amsterdam247%   Colombia     Colombia  T. manihoti Cajibio, 8/95 240 219 Amsterdam 91% T. manihotiCajibio,8/95240219Amsterdam91%   Colombia     Colombia 5/14/96 T. manihoti Guajira, 3/96 580 375 Amsterdam 65% 5/14/96 T. manihotiGuajira,3/96580375Amsterdam65%   Colombia     Colombia  T. manihoti Copacabana, 1/96 1,025 793 Amsterdam 77% T. manihotiCopacabana,1/961,025793Amsterdam77%   Colombia     Colombia 12/6/96 T. manihoti Bucaramanga, 8/96 480  Amsterdam ca. 60% 12/6/96 T. manihotiBucaramanga,8/96480Amsterdamca. 60%   Colombia (Los     Colombia (Los   Colorados)     Colorados) \" , Armenia, S/96 300  Amsterdam ca. 60% \",Armenia,S/96300Amsterdamca. 60%   Colombia     Colombia   Chinchina, 8/96 120  Amsterdam ca. 60% Chinchina,8/96120Amsterdamca. 60%   Colombia     Colombia  , Sta Rosa de 8/96 180  Amsterdam ca. 60% ,Sta Rosa de8/96180Amsterdamca. 60%   Cabal, Colombia     Cabal, Colombia \" , Bucaramanga, 8/96 180  Amsterdam ca. 60% \",Bucaramanga,8/96180Amsterdamca. 60%   Colombia     Colombia   (Bijagual)     (Bijagual) Sent to CNPMA quaranúne laboratory in Jaguariuna, Sao Paulo, for futher shipment to CNPMF, Bahia, Brazil. Sent to CNPMA quaranúne laboratory in Jaguariuna, Sao Paulo, for futher shipment to CNPMF, Bahia, Brazil. 2 Sent to quaranúne laboratory in Amsterdam, Holland, for futher shipment to liT A, Benin. 2 Sent to quaranúne laboratory in Amsterdam, Holland, for futher shipment to liT A, Benin.  "},{"text":"Table 4 . 1.3. Clima te associated with cultures of predatory phytoseiid mites exported from CIA T in 1996. Precipitation Temperature Dry Montbs RB Precipitation TemperatureDry MontbsRB  "},{"text":"Table 4 .1.4. Distribution of phytoseiid species with respect to elevation and number of dry months based on long-term climatic data associated with coUection sites in Colombia, Venezuela and Ecuador. No. of D ry Montbs Elevation above sea level (meten )  Typhlodrornalus manihoti    Typhlodrornalus manihoti   < 800 800-1200 1200-1600 > 1600 < 800800-12001200-1600> 1600  <3 0.54 0.25 0.25 0 .29 <30.540.250.250 .29  3-5 0.35 0.25 0.25 0.23 3-50.350.250.250.23  > 5 0.24    > 50.24 Neoseiulus anonyrnus     Neoseiulus anonyrnus   < 800 800-1200 1200-1600 >1600 < 800800-12001200-1600>1600 0.05 0.06 0.07 Galendromus annectens !-~ 1 0.15 0. 13 0.15 0.13 0.07 0.06 0.05 0.06 0.07 Galendromus annectens !-~ 10.15 0. 130.15 0.130.07 0.06   < 800 800-1200 1200-1600 > 1600 < 800800-12001200-1600> 1600 !-~ 1 Typhlodrornalus aripo 0.02 0.04 0.09 0. 10 0.05 0 .10 0.05 0 .03 !-~ 1 Typhlodrornalus aripo0.02 0.04 0.090. 10 0.050 .10 0.050 .03   < 800 800-1200 1200-1600 > 1600 < 800800-12001200-1600> 1600 0.03 0.05 0.05 Galendromus he1veo1us ~~~ 0.06 0.05 0.06 0.05 0.08 0.06 0.03 0.05 0.05 Galendromus he1veo1us ~~~0.06 0.050.06 0.050.08 0.06   < 800 800-1200 1200-1600 > 1600 < 800800-12001200-1600> 1600 m Neoseiulus idaeus 0.03 0.05 0. 10 0.08 0 .10 0.08 0.08 0.03 m Neoseiulus idaeus0.03 0.050. 10 0.080 .10 0.080.08 0.03   < 800 800-1200 1200-1600 > 1600 < 800800-12001200-1600> 1600 Euseius ho 0.01 ~~ 1 0.04    Euseius ho0.01 ~~ 1 0.04  < 3 < 800 800-1200 1200-1600 > 1600 < 3< 800800-12001200-1600> 1600  d 0.04 0.01 0.16 0.01 0.03 0 .01 0.03 0.05 0.03 d0.04 0.01 0.160.01 0.030 .01 0.030.05 0.03 TOTAL SAMPLE  Number of sites in each classification cell  TOTAL SAMPLENumber of sites in each classification cell   < 800 800-1200 1200-1600 > 1600 Total < 800800-12001200-1600> 1600Total !-~ 1 Total 11 1 728 245 1084 410 75 o 485 86 35 122 32 4 1 37 639 842 247 1728 !-~ 1 Total11 1 728 245 1084410 75 o 48586 35 12232 4 1 37639 842 247 1728  "},{"text":"Table 4 .1.5. Ifwe want to use phytoseüd species that have a close association with cassava, we should focus on the species in the upper part of the table. Typhlodromalus tenuisculus, N idaeus, Typhlodromips dentilis, T.  "},{"text":"Table 4 .1.5. Association of the 17 most common phytoseiid mites with cassava or other plants based on explorations in Colombia, Venezuela and Ecuador.     66 66 Phytoseüd species Proportion of field samples (%) Cassava Other plants Number of samples Phytoseüd speciesProportion of field samples (%) Cassava Other plantsNumber of samples Typhlodromalus tenuiscutus 91 3 • 64 Typhlodromalus tenuiscutus913 •64 Neoseiulus idaeus 96 4* 53 Neoseiulus idaeus964*53 Typhlodromips dentilis 96 4* 75 Typhlodromips dentilis964*75 Typhlodromalus manihoti 94* 6* 650 Typhlodromalus manihoti94*6*650 Galendromus helveolus 91 9* 102 Galendromus helveolus919*102 Galendromus annectens 88 12 116 Galendromus annectens8812116 Neoseiulus anonymus 86 14 181 Neoseiulus anonymus8614181 Typhlodromalus aripo 83 17 124 Typhlodromalus aripo8317124 Proprioseiopsis cannaensis 82 18 57 Proprioseiopsis cannaensis821857 Typhlodromalus peregrinus 82 18 49 Typhlodromalus peregrinus821849 Amblyseius aerialis 79 21 106 Amblyseius aerialis7921106 Typhlodromalus rapax 16 24 78 Typhlodromalus rapax162478 Phytoseiulus macropilis 10 30 43 Phytoseiulus macropilis103043 Euseius concordis 59* 41* 132 Euseius concordis59*41*132 Amblyseius chiapensis 51* 49* 47 Amblyseius chiapensis51*49*47 Euseius ho 50* 50* 129 Euseius ho50*50*129 Jphiseiodes zuluagai 31* 69* 78 Jphiseiodes zuluagai31*69*78  "},{"text":"Table 4 . 1.6. Species of Tetranychid mites held in the CIA T collection that show signs of infection b Neo •tes s . as indicated b the resence of h hal bodies. _ __ __;S;.¡; p'\"\" ec -'-i~s Samples Species Samples -•-- _ __ __;S;.¡; p'\"\" ec -'-i~sSamplesSpeciesSamples -•-- Eutetranychus banksi 1 Tetranychus canadensis 1 Eutetranychus banksi1Tetranychus canadensis1 Mononychellus caribbeanae 38 Tetranychus cinnabarinus 1 Mononychellus caribbeanae38Tetranychus cinnabarinus1 Mononychellus mcgregori 5 Tetranychus desertorum 1 Mononychellus mcgregori5Tetranychus desertorum1 Mononychellus planki 1 Tetranychus marianae 3 Mononychellus planki1Tetranychus marianae3 Mononychellus tanajoa 43 • Tetranychus mexicanus  Mononychellus tanajoa43 •Tetranychus mexicanus 0/igonychus gossypii 5 Tetranychus tumidus 4 0/igonychus gossypii5Tetranychus tumidus4 0/igonychus peruvianus 4 Tetranychus urticae 1 0/igonychus peruvianus4Tetranychus urticae1   Tetran chus s . 6 Tetran chus s .6 Total   115 Total115  "},{"text":"Table 4 . 1.7. Countries from which specimens ofTetranychid mites held in the CIAT collection show signs of infection by Neozygites sp. as indicated by the presence of hyphal bodies.  "},{"text":" 4.1.14). Various logical adjustments to the model were explored to see what changes would make the best fit to the experimental results. lncreasing the level of immature phytoseüd mortality, as a function of adult phytoseüd population permitted a very close fit to the results. This suggests that cannibalism is an important component that was not included in the original model. Based on this discovery we are initiating experiments to measure the rate of cannibalism, which should eventually help us to increase the efficiency of mass-rearing. Adult Female Mortality Adult Female Mortality / / / / / / / /  Fecundity ) Fecundity ) Eggs Food ) EggsFood ) Development ( Competition J Development( Competition J time  time Deutonymphs ( ____ s_ex_ra_t_io ___ ) Deutonymphs ( ____ s_ex_ra_t_io ___ ) ~ lmmature Mortality ~ lmmature Mortality  "},{"text":"Table 4 .1.8. List of phytoseiid species included in a dichotomous taxonomic key.  A mblyseius (Amblyseius) aerialis Neoseiulus anonymus A mblyseius (Amblyseius) aerialisNeoseiulus anonymus Amblyseius (Amblyseius) chiapensis Neoseiu/us califomicus Amblyseius (Amblyseius) chiapensisNeoseiu/us califomicus A mblyseius (Amblyseius) herbicolus Neoseiulus idaeus A mblyseius (Amblyseius) herbicolusNeoseiulus idaeus A mblyseius (Amb/yseius) largoensis Neoseiulus neotunus A mblyseius (Amb/yseius) largoensisNeoseiulus neotunus A mblyseius {lphiseiodis) zuluagai  A mblyseius {lphiseiodis) zuluagai A mblyseius (l'yphlodromalus) aripo Phytoseiulus macropilis A mblyseius (l'yphlodromalus) aripoPhytoseiulus macropilis A mblyseius (l'yphlodromalus) limonicus  A mblyseius (l'yphlodromalus) limonicus A mblyseius (l'yphlodromalus) manihoti Phytoseius purseglovei A mblyseius (l'yphlodromalus) manihotiPhytoseius purseglovei A mblyseius (l'yphlodroma/us) peregrinus  A mblyseius (l'yphlodroma/us) peregrinus Amblyseius (l'yphlodroma/us) rapax Proprioseiopsis cannaensis Amblyseius (l'yphlodroma/us) rapaxProprioseiopsis cannaensis Amblyseius (l'yphiodromalus) tenuiscutus Proprioseiopsis mexicanus Amblyseius (l'yphiodromalus) tenuiscutusProprioseiopsis mexicanus Amblyseius (l'yphlodromips) be//ottii Proprioseiopsis neotropicus Amblyseius (l'yphlodromips) be//ottiiProprioseiopsis neotropicus Amblyseius (l'yphlodromips) dentilis  Amblyseius (l'yphlodromips) dentilis Amblyseius (l'yph/odromips) mang/eae Typhlodromina tropica Amblyseius (l'yph/odromips) mang/eaeTyphlodromina tropica Euseius a/atus Typh/odromus (A nthoseius) transvaa/ensis Euseius a/atusTyph/odromus (A nthoseius) transvaa/ensis Euseius concordis  Euseius concordis Euseius ho  Euseius ho Galendromus annectens  Galendromus annectens Galendromus helveolus  Galendromus helveolus Genetic variability ofPhytoseiid \"species\"  Genetic variability ofPhytoseiid \"species\"  "},{"text":"Table 4 .1.9. List of documents scanned and formatted in Wordpeñect for conversion to bypertext to include in a CD-ROM being developed in coUaboration witb liTA and the University ofFiorida.   "},{"text":"Table 4 . 2.1 Natural enemies associated with whiteflies on cassava from surveys of tbree ecological zones (Andean, Llanos and North Coast) of Colombia. a farming and agro-ecological management approach. In 1996 the main CIAT activities were isolation of root and stem rot pathogens and development of isolation and inoculation methods and molecular technologies. Biological control experiments were conducted to select strains of Trichodenna spp. and Pseudomonas spp. antagonistic to fungal pathogens.   84 84 Species N Proportion (%) SpeciesNProportion (%) Parasitoids:   Parasitoids: Aphelinidae (Family)   Aphelinidae (Family) Encarsia hispida 1845 64.2 Encarsia hispida184564.2 Encarsia pergandiella 26 0.9 Encarsia pergandiella260.9 Encarsia bellottii 13 0.5 Encarsia bellottii130.5 Encarsia sp. 48 1.7 Encarsia sp.481.7 Eretmocerus sp. \"a\" 30 l. O Eretmocerus sp. \"a\"30l. O Eretmocerus sp. \"b\" 485 16.9 Eretmocerus sp. \"b\"48516.9 Eretmocerus sp. \"e\" 12 0.4 Eretmocerus sp. \"e\"120.4 Eretmocerus sp. 178 6.2 Eretmocerus sp.1786.2 P1atygasteridae (Family)   P1atygasteridae (Family) Amitus spiniferus 159 5.5 Amitus spiniferus1595.5 Amitus sp. 79 2.7 Amitus sp.792.7 Total 2875 100.0 Total2875100.0 Predators:   Predators: Coccinellidae (Fami1y)   Coccinellidae (Fami1y) Delphastus sp. 143  Delphastus sp.143 4.3 Plant pathology, by Elizabeth Alvarez and John B. Loke  4.3 Plant pathology, by Elizabeth Alvarez and John B. Loke In collaboration with PROFISMA, CNP.MFIEMBRAP A, EBDA, CORPOICA, Brazilian and In collaboration with PROFISMA, CNP.MFIEMBRAP A, EBDA, CORPOICA, Brazilian and  "},{"text":"Table 4 . 3.1. Phytopbthora root and stem rot diseases observed at 4 Colombian departments and their isolation.    Positive Recoveryl  Positive Recoveryl Collection Numberof     CollectionNumberof Si te Farms Visited Root Sprout Rhizosphere Number of Isolates Si teFarms VisitedRootSproutRhizosphereNumber of Isolates Cauca 10 _11  4 7 Cauca10_1147 Quin dio 15 3 2 12 41 Quin dio15321241 Valle 10 3 o 14 25 Valle103o1425 Bolivar  2 o o 2 Bolivar2oo2 1 number of farms from which Phytophthora spp. were isolated.   1 number of farms from which Phytophthora spp. were isolated.  "},{"text":"Table 4   "},{"text":"Table 4 .3.2. Fungal bioassays tested for root and sprout inoculations. Phytophthora spp. produces necrotic lesions on the stems, and the infected stem appears shrunken. Inoculated plants presented light brown or almost black discoloration of the stems. The first observable symptoms are brown patches on the petioles, and the older leaves tum yellow, then there is a loss ofturgidity anda general dieback of the whole plant occurs. Leaves eventually turn brown and do not fall off Significant differences in lesion expression caused by Phytophthora spp. was detected by inoculating cassava stems.Tolerant cultivars exhibited shorter or less intense lesions than the susceptible cultivars. The plants of sorne cultivars were killed, while others recovered by new sprouts.      89 89 Parameter Root Root & Sprout Sprout  ParameterRootRoot & SproutSprout Plant slice of swollen cylinder of potted plant of 3 wi<C potted plant of 4 wkc excised shoot Plantslice of swollencylinder ofpotted plant of 3 wi<Cpotted plant of 4 wkcexcised shoot material root<l swollen rootb   of22 wkC materialroot<lswollen rootbof22 wkC Technique disc in center of cylinder placed application of fragment on 5 mm cut sprout in Techniquedisc in center ofcylinder placedapplication offragment on 5 mmcut sprout in  each slice vertical i!l . suspensiond to soil; wound of stem suspensiond each slicevertical i!l .suspensiond to soil;wound of stemsuspensiond   suspensiond flooding of soil and   suspensiondflooding of soil and    removing foliage   removing foliage Incubation cellophane in plastic box in screenhouse greenhouse glass tubes in Incubationcellophane inplastic box inscreenhousegreenhouseglass tubes in conditions incubator lab.   lab. conditionsincubatorlab.lab. Evaluation 14 14 14 28 28 Evaluation1414142828 periode      periode Efficiencyf 24 24 15 15  Efficiencyf24241515 a 1.5 cm x approxirnately 5 cm.     a 1.5 cm x approxirnately 5 cm. b 1.5 cm x 3 cm.     b 1.5 cm x 3 cm. e propagated by stem cutting.     e propagated by stem cutting. d 1,0 x 10 5 spores/ml.     d 1,0 x 10 5 spores/ml. e d after inoculation.     e d after inoculation. f average number of inoculations per field plant.    f average number of inoculations per field plant.  "},{"text":"Table 4 . 3.3. Results of laboratory and greenhouse bioassays of P. drechsleri and P. nicotianae {P.f!.arasitica} inoculated on cassava cultivars. Out of 200 cultivars, all in the core germplasm collection, 61 expressed Phytophthora leafblight disease. In plants a general blight (yellow leaves and/or necrotic lesions on sprouts) was observed 3-5 wk after planting stem cuttings. Cassava plantlets in the greenhouse can be predisposed to the severe expression of stem rot if the soil in the pots is allowed to dry to near the wilting poÍ!lt before excessive watering. About 3 ha of commercial cassava production was severely affected by root and stem rots, the field was infested with Phytophthora spp. which was isolated from irrigation water, soil and cassava sprout tissue. In plants a general dieback was observed 3 months after planting stem cuttings, 7 months later the swollen roots were rotten. Under less favorable conditions for the fungus, the plants recuperated. Most plants at all stages of growth from germination to maturity showed symptoms. It is concluded that under severe conditions or severe infection plants may be killed, but in plants that survive the stakes are infected.Phytophthora strains were obtained from 34 cassava fanns of the Colombian departments Valle, Quindio, Cauca and Bolivar. Ten strains were compared in virulence tests. Virulence was determined by inoculating cassava plants by stem wounding. The effectiveness of this procedure in distinguishing the severity of disease reactions produced by different strains was evaluated.Considerable variation in lesion size was observed. The symptoms caused by individual strains of Phytophthora species were very similar, although symptom severity differed among strains and species. The virulence testing of76 strains is ongoing.   Root 1   S~routl   Root 1S~routl Pathogen & cassava cultivar Whole Slice C;rlinder Soil Soil Wound Excised S~rout Field Reaction2 Pathogen & cassava cultivarWholeSliceC;rlinderSoilSoilWoundExcised S~routField Reaction2 P. drechsleri         P. drechsleri CG 1355-2 R S S S R R RIS  CG 1355-2RSSSRRRIS MCOL 2280 R S S R R RIS R  MCOL 2280RSSRRRISR MCOL 1505 S S _3 R S S R  MCOL 1505SS_3RSSR MBRA 1045  S S R R R  R MBRA 1045SSRRRR MBRA532 4 S  S   RIS RIS R MBRA532 4SSRISRISR P. nicotianae         P. nicotianae MCR54 S S R S RIS RIS RIS  MCR54SSRSRISRISRIS MCOL 2280 RJS R S S RIS S S  MCOL 2280RJSRSSRISSS CG 1355-2  S S S RIS RIS S  CG 1355-2SSSRISRISS MCOL 1505  S S S S S S  MCOL 1505SSSSSS MBRA5324  S R   S RIS R MBRA5324SRSRISR 2 According to farmers.         2 According to farmers. 3 Not sufficient plant material available.       3 Not sufficient plant material available. 4 Variety Ossoduro.         4 Variety Ossoduro. Resistance to root rot not necessarily implies resistance to Ieafblight and vice versa. To be Resistance to root rot not necessarily implies resistance to Ieafblight and vice versa. To be sure of an adequate root inoculation test other field resistant and susceptible cultivars have to be sure of an adequate root inoculation test other field resistant and susceptible cultivars have to be identified and inoculated.        identified and inoculated. Cassava infected by Phytophthora spp. at CIA T      Cassava infected by Phytophthora spp. at CIA T Phytophthora root rot and leafblight were not previously considered to be important limiting Phytophthora root rot and leafblight were not previously considered to be important limiting factors for cassava stake production at CIAT. By use ofadvanced isolation methods it was factors for cassava stake production at CIAT. By use ofadvanced isolation methods it was  "},{"text":"Table 4 . 5.1 Effect of NPK rates on dry root yield and dry plant top (t/ha) of two cassava varieties during the 1995-1996 season (13th cycle) at Santander de Quilichao, Cauca, Colombial. Tukey) for comparison between NPK treatments for dry root 3.75, for dry top 1.57. Fertilizer treatment (kglba) M Col1684 CM 91-3  Fertilizer treatment (kglba)M Col1684CM 91-3 N p K Dry root Dry top Dry root Dry top NpKDry rootDry topDry rootDry top o o o -4.4 2.0 3.9 2.3 ooo-4.42.03.92.3 50 50 50 9.1 3.5 7.8 3.9 5050509.13.57.83.9 o lOO lOO 10.4 3.3 5.2 2.9 o lOOlOO10.43.35.22.9 50 100 lOO 10.1 4.4 7.8 3.8 50100lOO10.14.47.83.8 lOO lOO lOO 10.5 4.3 9.2 3.9 lOOlOOlOO10.54.39.23.9 lOO o lOO 9.8 4.0 8.9 4.-l lOOolOO9.84.08.94.-l lOO 50 lOO 13.0 4.2 8A 3.8 lOO50lOO13.04.28A3.8 lOO lOO o 7.5 3.0 5.2 3.1 lOOlOOo7.53.05.23.1 lOO lOO 50 10.3 4.0 7.6 4.1 lOOlOO5010.34.07.64.1 LSD 5% (       LSD 5% (  "},{"text":"Table 4 .5.2 Dry root yield and dry plant top (tlba) of cassava (cv. M Col 1505) at Media Luna, Magdalena, Colombia during the season 1995-1996 (8th cropping e ele. Values in columns followed by the same letters are not significantly different at 5% by Duncan' s test.  Fertilized 1   Unfertilized Fertilized 1Unfertilized Treatment Root Top Root Top TreatmentRootTopRootTop Conventional tillage 4.3bc3 2.4b l.2b l.4b Conventional tillage4.3bc32.4bl.2bl.4b Conventional tillage + muJch2 5.9ab 3.6ba 4.6a 2.7a Conventional tillage + muJch25.9ab3.6ba4.6a2.7a Zero tillage 3.3c 2.3b l.4b 1.2b Zero tillage3.3c2.3bl.4b1.2b Zero tillage + mulch 6. 9a 4.2a 4.9a 2.8a Zero tillage + mulch6. 9a4.2a4.9a2.8a 1 Fertilized with 330 kg/ha 15-15-15 NPK (50 N; 21.6 P; 41 .7 K kglha).   1 Fertilized with 330 kg/ha 15-15-15 NPK (50 N; 21.6 P; 41 .7 K kglha). 2 Mulch, 12 tlha dry grasses applied annually.    2 Mulch, 12 tlha dry grasses applied annually. 3     3  "},{"text":"Table 4 . 5.3Dry root yield and dry top (tlha) and root dry matter (%) (cv. CM 523-7 and CM 507-37) at Santander de Quilichao, Cauca, Colombia. First season{1995-1996). CM 523-7 CM 523-7  "},{"text":" Phytoseiid mi tes were released in cassava fields located in the S tates of Bahía and Pernambuco, as shown in Table5.1.2. Releases were performed late aftemoon, by attaching phytoseiid infested cassava lea ves to cassava branches. A total of 10,813 individuals of T. 108 108 5.1 Biological Control of the Cassava Green Mite, by Aloyseia Cristina S. Noronha 5.1 Biological Control of the Cassava Green Mite, by Aloyseia Cristina S. Noronha lntroduction of phytoseiid mites lntroduction of phytoseiid mites Individuals of Typhlodromalus tenuiscutus McMurtry & Moraes were collected in Individuals of Typhlodromalus tenuiscutus McMurtry & Moraes were collected in Puerto Cayo, Manabi Ecuador anº sent from CIA T to the \"Costa Lima\" Quarantine Puerto Cayo, Manabi Ecuador anº sent from CIA T to the \"Costa Lima\" Quarantine Laboratory, El\\1BRAP A/CNPMA, municipality of Jaguariúna, State of Sao Paulo. During Laboratory, El\\1BRAP A/CNPMA, municipality of Jaguariúna, State of Sao Paulo. During 1996, five shipments of T tenuiscutus were made from EMBRAP A/CNPMA to 1996, five shipments of T tenuiscutus were made from EMBRAP A/CNPMA to EMBRAPA/CNPMF anda total of2, 150 individuals were sent, 75.48% ofthem arrived EMBRAPA/CNPMF anda total of2, 150 individuals were sent, 75.48% ofthem arrived alive. As stated in PROFISMA' s Annual Report 1995, T tenuiscutus shipments from CIA T alive. As stated in PROFISMA' s Annual Report 1995, T tenuiscutus shipments from CIA T during 1996 were with recently established colonies. during 1996 were with recently established colonies. Maintenance rearing Maintenance rearing Using an adaptation ofMcMutry & Scriven's phytoseiid rearing method, it was possible Using an adaptation ofMcMutry & Scriven's phytoseiid rearing method, it was possible to obtain a monthly average production of about 2,500 individuals of N californicus per tray to obtain a monthly average production of about 2,500 individuals of N californicus per tray onjack bean (Canavalia ensiformis) detached leaves, under laboratory conditions, at onjack bean (Canavalia ensiformis) detached leaves, under laboratory conditions, at EMBRAP A/CNPMF (Table 5. l . 1 ). EMBRAP A/CNPMF (Table 5. l . 1 ). Mass rearing Mass rearing T. tenuiscutus rearing was performed under laboratory conditions on M tanajoa on T. tenuiscutus rearing was performed under laboratory conditions on M tanajoa on detached cassava leaves. Mass rearing of N californicus was carried out in a screenhouse. detached cassava leaves. Mass rearing of N californicus was carried out in a screenhouse. Individuals were fed on Tetranychus urticae on jack bean plants. Such a methodology Individuals were fed on Tetranychus urticae on jack bean plants. Such a methodology enabled the production of33 ,500 individuals of N californicus starting from a single colony, enabled the production of33 ,500 individuals of N californicus starting from a single colony, in a one month period. in a one month period. Release and monitoring of phytoseiid mites Release and monitoring of phytoseiid mites  "},{"text":"Table 5 . 1.1. Maintenance rearing of Neoseiulus californicus, on detached leaves of Canavalia ensiformis, under laboratory conditions. Number Number  "},{"text":"Table 5 . 1.2. Field releases of phytoseiid mites. S~ecies S tate Munici(!ality Field lndividuals Relea ses S~eciesS tateMunici(!alityFieldlndividuals Relea ses r tenuiscutus Bahia Juacema Juacema 600 1 r tenuiscutus BahiaJuacemaJuacema6001   Jaguari Jaguari 10,213 50 JaguariJaguari10,21350 Total    10,813 Total10,813 N californicus Bahia C. Almas EAUFBA 3,000 1 N californicus BahiaC. AlmasEAUFBA3,0001   lchu Ichu 8,070 2 lchuIchu8,0702   Jaguari Jaguari 19, 950 JaguariJaguari19, 950  Pernambuco Petrolina Ad 3,000 4 Pernambuco PetrolinaAd3,0004 Total    34,020 Total34,020 Monthly monitoring recovered 1, 085 mi tes from all cassava fields where releases were Monthly monitoring recovered 1, 085 mi tes from all cassava fields where releases were performed. One hundred and forty-two slides were examined under microscope enabling performed. One hundred and forty-two slides were examined under microscope enabling preliminary identification of28 phytoseiid mites, resembling N calif ornicus; slides were sent preliminary identification of28 phytoseiid mites, resembling N calif ornicus; slides were sent to Dr. G. de Moraes to confirm the identifications.   to Dr. G. de Moraes to confirm the identifications. Effect of neem, Azadirachta indica A. Juss, on mites  Effect of neem, Azadirachta indica A. Juss, on mites  "},{"text":"Table 5 . 1.6. Conidial production of six Neozygites sp. isolates, stored for eight and Values followed the same letter, in the same column, do not differ significantly (P=0.05).  eighteeo months at 4°C/5% RH (total number of conidia produced per eighteeo months at 4°C/5% RH (total number of conidia produced per  single mummyfied M tanajoa, after 24 hours uoder dark cooditions aod single mummyfied M tanajoa, after 24 hours uoder dark cooditions aod  100% RH).  100% RH).  Total conidia produced per CGM mummy 1 Total conidia produced per CGM mummy 1 Isolate 8 month storage period 18 month storage period Isolate8 month storage period18 month storage period 4 569±95 a 417±210 a 4569±95 a417±210 a 15 356±70.9 a 430±261 a 15356±70.9 a430±261 a 20 1284±231 a 132±229 b 201284±231 a132±229 b 21 393±195a 197±3 19 a 21393±195a197±3 19 a 22 748±133 a 0±0 b 22748±133 a0±0 b 25 963±191a 261±312 b 25963±191a261±312 b 1   1  "},{"text":" Viability of two Neozygites sp. isolates stored under several conditions.Phenotyp ic characterization of Neozygites sp. isolatesSince no information is available in the literature regarding to phenotypic characterization of Neozygites sp., basic research was conducted aiming at developing the methodology necessary to carry out that activity. Studies were initially directed to determine the effect ofrelative humidity on sporulation, and length oftime of conidial production of Neozygites sp. isolates. It was observed that the isolates from Cruz das Almas and Piritiba do not sporulate relative humidity lower than 95% at 24°C (Figure5.1.2). Consequently , 95%   Isolate from  Isolate from • 40C e 37o/o R.H. O 4°C e 21o/o R.H. • 250C e 50% R. Cruz das Almas a • 40C e 37o/o R.H. O 4°C e 21o/o R.H. • 250C e 50% R.Cruz das Almasa     b b 7 days 1 rronth 2 rronths 4 rronths 8 roonths 7 days1 rronth2 rronths4 rronths8 roonths    Storage period Storage period O -100C O 40C e 5o/o RH. Isolate from Piritiba  O -100C O 40C e 5o/o RH.Isolate from Piritiba • 40C e 37o/o R. H.    • 40C e 37o/o R. H. O 40C e 21o/o R.H. • 250C e 50% R.H.   a ab ab O 40C e 21o/o R.H. • 250C e 50% R.H.a ab ab 7 days 1 rmnth 2 rronths 4 rronths 8 roonths 7 days1 rmnth2 rronths4 rronths8 roonths    S torage period S torage period Figure 5.1.1.     Figure 5.1.1.  "},{"text":"Table 5 .1.7. Conidial production of 12 Neozygites sp. isolates kept under 24°C and 100% RH Values followed by the same letter, in the same eolumn, do not differ signifieantly (P=0.05).        115 115   1 •    1•   6 bours 9 bours 12 bours 6 bours9 bours12 bours  Primary   Primary  Primary PrimaryPrimaryPrimary Iisolate conidia Ca~illiconidia conidia Ca~illiconidia conidia 1 Ca~illiconidia IisolateconidiaCa~illiconidiaconidiaCa~illiconidiaconidia 1Ca~illiconidia 18 0.0±0.0 0.0±0.0 9.4±20.3 0.0±0.0 1.5±4.7 e 0.0±0.0 180.0±0.00.0±0.09.4±20.30.0±0.01.5±4.7 e0.0±0.0 22 2.5±7.9 0.0±0.0 23. 1±57.4 0.0±0.0 1.8±3 .9 e 0.0±0.0 222.5±7.90.0±0.023. 1±57.40.0±0.01.8±3 .9 e0.0±0.0 04 0.0±0.0 0.0±0.0 49.7±136.2 0.0±0.0 13.6±22.7 be 0.0±0.0 040.0±0.00.0±0.049.7±136.20.0±0.013.6±22.7 be0.0±0.0 10 0.6±1.9 0.0±0.0 58.4±121.6 0.0±0.0 14.8±31.3 be 0.0±0.0 100.6±1.90.0±0.058.4±121.60.0±0.014.8±31.3 be0.0±0.0 01 47.9±149 0.0±0.0 90.8±129.3 0.0±0.0 168.5±226.8ab 0.0±0.0 0147.9±1490.0±0.090.8±129.30.0±0.0168.5±226.8ab0.0±0.0 08 10.3±31.2 0.0 ±0.0 57. 1±83 .5 0.0±0.0 203 .6±205.7a 2.4±7.6 0810.3±31.20.0 ±0.057. 1±83 .50.0±0.0203 .6±205.7a2.4±7.6 11 0.0±0.0 0.0±0,0 3.0±9.5 0.0±0.0 39.6±102.6 be 0.0±0.0 110.0±0.00.0±0,03.0±9.50.0±0.039.6±102.6 be0.0±0.0 21 0.0±0.0 0.0±0.0 25.0±55.8 0.0±0.0 5.0±15.8 be 0.0±0.0 210.0±0.00.0±0.025.0±55.80.0±0.05.0±15.8 be0.0±0.0 15 0.0±0.0 0.0±0.0 51.3±108.5 0.0±0.0 52. 1± 113.-labe 0.0±0.0 150.0±0.00.0±0.051.3±108.50.0±0.052. 1± 113.-labe0.0±0.0 20 1.0±3. 2 0.0±0.0 35.4±57.6 0.0±0.0 64.9±73.8abe 3.8±12.0 201.0±3. 20.0±0.035.4±57.60.0±0.064.9±73.8abe3.8±12.0 25 0.0±0.0 0.0±0.0 65. 1± 157. 1 0.0±0.0 72.6±1 12.6abe 0.0±0.0 250.0±0.00.0±0.065. 1± 157. 10.0±0.072.6±1 12.6abe0.0±0.0 13 0.0±0.0 0.0±0.0 45 .6±82.5 0.0±0.0 76.8±94.2abe 0.0±0.0 130.0±0.00.0±0.045 .6±82.50.0±0.076.8±94.2abe0.0±0.0 1       1  "},{"text":"Table 5 . 1.8. Specificity of Neozygites sp. isolates to Mononychellus tanajoa and Tetranychus urticae.  Infection  Infection Isolate collecting place M. tanajoa T. urticae Isolate collecting placeM. tanajoaT. urticae Cali, Colombia* + + Cali, Colombia*++ Caruarú, Pernambuco +  Caruarú, Pernambuco+ Cristinápolis, Sergipe +  Cristinápolis, Sergipe+ Croatá, Ceará +  Croatá, Ceará+ Cruz das Almas, Babia +  Cruz das Almas, Babia+ Gravatá, Pernambuco +  Gravatá, Pernambuco+ Ipirá, Bahia +  Ipirá, Bahia+ Itaberaba, Babia +  Itaberaba, Babia+ Itapajé, Ceará +  Itapajé, Ceará+ Jaguariúna, Sao Paulo* +  Jaguariúna, Sao Paulo*+ Lambari, Minas Gerais +  Lambari, Minas Gerais+ Mandiocaba, Paraná +  Mandiocaba, Paraná+ Piritiba, Bahía +  Piritiba, Bahía+ P . Real do Colégio, Alagoas +  P . Real do Colégio, Alagoas+ Rio Real, Bahía +  Rio Real, Bahía+ Sao M. das Matas, Bahía +  Sao M. das Matas, Bahía+ Teotonio Vilela, Alagoas +  Teotonio Vilela, Alagoas+ Tianguá, Ceará +  Tianguá, Ceará+ Vit. Sto. Antao, Pernambuco +  Vit. Sto. Antao, Pernambuco+ * Isolate from T urticae   * Isolate from T urticae Neozygites sp. inoculation under field conditions   Neozygites sp. inoculation under field conditions  "},{"text":" 5.1.3. Population dynamic of Neozygites sp. and Mononychellus tanajoa in two cassava fields located in Piritiba, Bahia (.J., Indica te inoculation date). CGM density score 1= <25, 2= >25<200 and 3= >200 miteslleaf.5.2 BIOLOGICAL CONTROL OF THE CASSA VA MEALYBUG (CM), by José Mauricio Simoes Bento Mauricio Simoes Bento Mass rearing and releasing parasitoids of the cassava mealybug Mass rearing and releasing parasitoids of the cassava mealybug Apoanagyrus (=Epidiniocarsis) diversicornis, Acerophagus coccois and Aenasius vexans, Apoanagyrus (=Epidiniocarsis) diversicornis, Acerophagus coccois and Aenasius vexans, all parasitoids ofthe cassava mealybug, Phenacoccus herreni, were introduced from CIAT, all parasitoids ofthe cassava mealybug, Phenacoccus herreni, were introduced from CIAT, through the \"Costa Lima\" Quarantine Laboratory, EMBRAP A/CNPMA, to EMBRAP Al through the \"Costa Lima\" Quarantine Laboratory, EMBRAP A/CNPMA, to EMBRAP Al CNPMF where those parasitoids were mass-reared. A total of 111,610 parasitoids were CNPMF where those parasitoids were mass-reared. A total of 111,610 parasitoids were produced, 35,950 ofwhich were released in three cassava fields in the State ofBahia and produced, 35,950 ofwhich were released in three cassava fields in the State ofBahia and three cassava fields in the State ofPemambuco, showing high leve! ofincidence ofthe three cassava fields in the State ofPemambuco, showing high leve! ofincidence ofthe cassava mealybug (Table 5.2.1). cassava mealybug (Table 5.2.1).  "},{"text":"Table 5 . 2.1. Number of cassava mealybug parasitoids produced under laboratory conditions, at EMBRAPA/CNPMF, and released in cassava fields located in the S tates of Babia and Pernambuco.  "},{"text":"Biological control of P. he\"eni .~ ................................................... J.~.?.~ .......................................................... ~.22.~ ............................ . . diversicornis showed higher dispersion ability than A. coccois andA. vexans, reachíng 130 km from the releasing site by January 1995, 234 km by September 1995, and 304 km by ApriV1996. A. coccois dispersed slowly, reaching 180 km from the releasing site by September/1995, while A. vexans has not dispersed in the State ofBahia as of November 1996 des pite the large number of releases airead y performed. Parasitoid releases of A.Paraitoid monitoring has been carried out every two weeks, since the first release back in 1994. Results show a significant decrease on number of CM per plant dueto parasitoid action. A positive correlation between number of parasitoids and CM control has al so been observed for both A. diversicornis andA. coccois in the S tate of Bahía (Figure5.2. 1 ). Field observations have demonstrated ~hat A. diversicornis has high dispersa! and survival abilities, but it is less aggressive than A. coccois which demonstrates a very high ability to control the cassava mealybug, especially when at high populations. Such a situation has been observed in Itaberaba, S tate ofBahia, where A. coccois, probably because of its ability to attack early stages (instars) ofthe pest, has shown a better biocontrol effect than A. diversicornis. Species Produced Released BA PE Produced Released BA PE Produced Released BA PE SpeciesProducedReleased BA PE ProducedReleased BA PEProducedReleased BA PE E. diversicornis 6. 190 3,010 310 5,235 3,720  5,901 640 E. diversicornis6. 190 3,0103105,235 3,7205,901640 A . cocois 9,950 1,950  11 ,566 500 750 53 .229 11 ,100 4,050 A . cocois9,950 1,95011 ,56650075053 .229 11 ,1004,050 A . vexans    9,043 2,980 2,000 10,496 3,020 1,900 A . vexans9,043 2,980 2,00010,4963,0201,900 Total 16,140 4,960 310 25,844 7,200 2,750 69,626 14,760 5,950 Total16,140 4,96031025,844 7,200 2,75069,626 14,7605,950 Parasitoid dispersion      Parasitoid dispersion coccois andA. vexans started in the State ofPernambuco in August 1995, and by November coccois andA. vexans started in the State ofPernambuco in August 1995, and by November 1996 a total of9,010 indíviduals had been released. lndividuals have already been recaptured 1996 a total of9,010 indíviduals had been released. lndividuals have already been recaptured 40 km away from the release site.     40 km away from the release site.  "},{"text":" CASSA VA CROP MANAGEMENT, by José Eduardo Borges de CarvalhoEffect of weeds on cassava yield Weed competition in the cassava crop may cause yield reduction as high as 40%, for both roots and aerial plant parts, if weeding is not performed at the right time during the crop cycle, mainly in ecosystems where the water availability is deficient in the soil. Weeds also act as source of food and shelter for arthropods, either pest or beneficia! organisms, as shown in Table5.3.1 and in previous PROFISMA's Annual Reports.Table 5.3.1. Relative distribution of various classes of arthropods on weeds commonly found in cassava fields in the municipalities of Itaberaba and Piritiba, S tate of Babia. Studies on weed effects on cassava yield, carried out in past years in Itaberaba and Piritiba municipalities, State ofBahia, showed that in Itaberaba the cassava root yield was very low, and consequently no significant difference for treatment was observed. In the experiment installed in Piritiba, the control treatment (without weed control) produced only 3.35 metric tons/ha, a root production sígnificantly lower than the other treatments evaluated in that region (Table 5.3.2). Although stilllow, root yield in Piritiba was higher than in Itaberaba. Such a low root yield, and no significance for treatment in the experiment installed in Itaberaba, seems to be due to a very drastic decrease in rainfall, starting from September, similar to prevíous observations (PROFISMA' s Annual Report 1995). Besides the low rainfall, an unpredicted homworm attack may have also affected the cassava root yield in the experiment installed in Itaberaba. The results from the effect of weeds on cassava yield give a strong indication that weeding can start 30 days after cassava germination and continue up to five months. Itaberaba and Piritiba. It is well known that, dueto its initial slow growth, a large portian of a cassava field is exposed to the impact of rain which causes soilloss by surface run-off. Regarding erosion control, a very low soilloss resulted from planting either jack bean or cowpea between cassava double rows (PROFISMA' s Annual Report 1995). Another tria! was planted in the same area during the 1996 growing season in arder to continue this type of evaluation. Due to a very drastic ~rought in Piritiba, no soilloss by surface run-off was recorded. Raining resumed by late December 1996, and results will be presented in the 1997 Annual Report. Table 5.3.3 shows data related to the effect of cover crop on arthropod populations in cassava fiel d. Results show that cover crops, either legume or weeds, act as source of food and shelter for both natural enemies and pests. The high amount of natural enemies found on weeds (22.6%) suggests the importance ofweed management on setting up biocontrol strategies for cassava pests. Table 5.3.3. Frequency of arthropods on cover crops in cassava fields in the municipalities of Cruz das Almas, ltaberaba, and Piritiba, State of Bahía . Regarding to root yield as affected by cover crops, the joint analyses ofthe 1995-1996 growing season presented in Table 5.3.4 show that weed control over entire crop enabled the highest root yield in Cruz das Almas, and in Piritiba. On the other hand, weed control within double rows/weed between double rows, resulted in the lowest yields in both ecosystems, probably due to competition for water during period of low water availability in the soil. No significant decrease on cassava root yield by neither pigeon pea (Cajanus cajan), jack bean nor cowpea was observed in Piritiba. In Cruz das Almas, jack bean depressed cassava root yield, but this behavior seems to be due to other problems that caused yield reduction in replicate two rather than competition by the cover crop. Although showing the highest root yield, weed control over entire crop raised production costs over 30% as compared with treatment four (weed control within double rows/jack bean between double rows). Table 5.3.4. Joint analysis of eassava root yield for the 1995/1996 growing seasons, in Piritiba and Cruz das Almas.. ............................ ~. ~-~. !.Y.~.~!~ .. l• FMA M JJ A S ON 1995 5.3 Cassava DJ 1994 pests Table 5.3.2. Joint analyses of cassava root yield as affected by weed competition ~~ + '¡ ¡-SON DJF MAM J JA 1996 SO N 4 3 2 o Other Natural Other crops pests Enemies Insects Weed s~ecies {%} {%} {%} (1995/1996 growing seasons). {%} Blainvillea rhomboidea 55.5 33 .3 Yield (t/ha) 1 11.2 Acanthospermum hispidum 14.3 57.1 Treatments Itaberaba Piritiba 28.6 Diodia teres 22.2 55 .5 Weed control from germination 22.3 Croton lobatus 25 .0 25 .0 25.0 For 90 days 2.09 a 8.42 a 25 .0 Croton gladulosus 16.7 33.3 16.7 For 120 days 2.82 a 8.68 a 33.3 Passiglora cincinnata 16.7 33.3 33.3 For 150 days 3.41 a 9.16 a 16.7 Mitracarpus hirtus 16.7 50.0 For 180 days 3.02 a 8.39 a 33 .3 Polygata violacea 20.0 60.0 For 2 10 days 2.96 a 7.60 a 20.0 Borreira sp. 57.1 20,6 Arthropods Legume Weeds Weed control beginning 30 days after germination 14.3 Eupatorium ballataefolium 40.0 For 60 days 2 .54 a Cassava pests 16.0 21.5 7.9 1 a 60.0 Wissandula subpeltata 57.1 14.3 For 90 days 2.72 a Other crop pests 75.0 33 .0 9.53 a 28.6 Cassia rotundifolia 16.7 33.3 33.3 For 120 days 2.43 a Natural enemies 9.0 22.6 8.33 a 16.7 Setaria vulpiseta 14.3 57.1 For 150 days 3.06 a Others 0.0 22.9 8.67 a 28.6 Acathospermum austra/e 25 .0 50.0 Sida cordifolia 33 .3 Eupatorium laevigatum 42.8 28.6 28.6 Without weed control 0.70 a 3.35 b 33 .3 33.4 Weed control throughout crop cycle 2. 7 1 a 8.22 a 25.0 For 180days 2.36 a 8.44 a Total 100.0 100.0 l• FMA M JJ A S ON 1995 5.3 Cassava DJ 1994 pests Table 5.3.2. Joint analyses of cassava root yield as affected by weed competition ~~ + '¡ ¡-SON DJF MAM J JA 1996 SO N 4 3 2 o Other Natural Other crops pests Enemies Insects Weed s~ecies {%} {%} {%} (1995/1996 growing seasons). {%} Blainvillea rhomboidea 55.5 33 .3 Yield (t/ha) 1 11.2 Acanthospermum hispidum 14.3 57.1 Treatments Itaberaba Piritiba 28.6 Diodia teres 22.2 55 .5 Weed control from germination 22.3 Croton lobatus 25 .0 25 .0 25.0 For 90 days 2.09 a 8.42 a 25 .0 Croton gladulosus 16.7 33.3 16.7 For 120 days 2.82 a 8.68 a 33.3 Passiglora cincinnata 16.7 33.3 33.3 For 150 days 3.41 a 9.16 a 16.7 Mitracarpus hirtus 16.7 50.0 For 180 days 3.02 a 8.39 a 33 .3 Polygata violacea 20.0 60.0 For 2 10 days 2.96 a 7.60 a 20.0 Borreira sp. 57.1 20,6 Arthropods Legume Weeds Weed control beginning 30 days after germination 14.3 Eupatorium ballataefolium 40.0 For 60 days 2 .54 a Cassava pests 16.0 21.5 7.9 1 a 60.0 Wissandula subpeltata 57.1 14.3 For 90 days 2.72 a Other crop pests 75.0 33 .0 9.53 a 28.6 Cassia rotundifolia 16.7 33.3 33.3 For 120 days 2.43 a Natural enemies 9.0 22.6 8.33 a 16.7 Setaria vulpiseta 14.3 57.1 For 150 days 3.06 a Others 0.0 22.9 8.67 a 28.6 Acathospermum austra/e 25 .0 50.0 Sida cordifolia 33 .3 Eupatorium laevigatum 42.8 28.6 28.6 Without weed control 0.70 a 3.35 b 33 .3 33.4 Weed control throughout crop cycle 2. 7 1 a 8.22 a 25.0 For 180days 2.36 a 8.44 a Total 100.0 100.0 Figure 5.2.1. Population dynamics of cassava mealybug (CM) Phenacoccus Solanum erianthum 62.5 12.5 Values fo llowed by the same letter in the same column, do not differ significantly 25.0 Average 21.5 33.0 22.6 22.9 (P=0.05), according to Tukey' s test. Figure 5.2.1. Population dynamics of cassava mealybug (CM) Phenacoccus Solanum erianthum 62.5 12.5 Values fo llowed by the same letter in the same column, do not differ significantly 25.0 Average 21.5 33.0 22.6 22.9 (P=0.05), according to Tukey' s test. herreni (second to fourth instars) in cassava fields where herreni (second to fourth instars) in cassava fields where Apoanagyrus (=Epidinocarsis) diversicornis and Acerophagus coccois were released from 1994 to 1996 (Arrow indicates first release). Effect of cover crops on cassava yield, arthropod population and erosion control Apoanagyrus (=Epidinocarsis) diversicornis and Acerophagus coccois were released from 1994 to 1996 (Arrow indicates first release). Effect of cover crops on cassava yield, arthropod population and erosion control  "},{"text":"Table 5 . 3.5. Effect of the bagana mulching on the cassava root yield, a erial part and starch content at Acaraú, Sta te of Ceará. Yield {ton/ha} 1 Yield {ton/ha} 1 Starch content Starch content  "},{"text":"Table 5 . 3.6. Effect of bagana mulching on the cassava root yield, aerial part and starch content at Russas, Sta te of Ceará.The experiment installed in Acaraú, in February 1996, shows normal development; on the other hand the experiment in Russas presented problems related to germínation probably due to high soil temperature in the bagana covered plots. Both trials will be harvested by July 126 126  "},{"text":"1 Cassava Witches' Broom Disease Cultural Control of Cassava Witches' Broom Disease   "},{"text":"Table 5 .4.2.2. On-farm evaluation of 18 cassava genotypes for root rot incidence, in the rural community \"Engenho Mares\", municipality of Alagoa Grande, S tate of Paraiba. - Results of a simplified phytosanitary diagnostic survey, carried out during 1994 in the Serrada Ibiapaba cassava growing region, showed that one ofthe most important factors involved in the CWBD spread throughout the region ís the sharing of planting material, a very common practice among cassava growers. Such a behavior gíves an indication that the selected CWBD resistant clones would be dispersed within rural communities by sharing planting material. A very strong support to this assumption is the observation that, the stem of several selected clones had already been removed by cassava growers prior to harvest and, according to them, used for either replacing their own field or donating to other cassava growers.It is interesting to mention that growers' preferences for the evaluated cassava clones/varieties were ~ 60% for the clones 8709-2, 8952-6 and 8911-16 as compared with 15% to 35% for the local variety Cruvela. Increase in adoption level ofthe selected clones is expected through action of the EMA TER CE by ditfusion methodologies. Considering 60% adoption ofthe CWBD resistant clones, this would imply in a replacement of about 3,000 ha ofthe susceptible variety Cruvela. Considering the root yield potential ofthe selected clones, around 20 metric ton/ha, such replacement would representa 60,000 metric ton yield. Isolations carried out under laboratory conditions showed that the pathogens involved in the cassava root rot development in the evaluated rural communities in the State ofBahia were Fusarium sp., Phytophthora sp., or Scytalidium lignicola.The trial installed in the COP AL Chapada was aimed at evaluating the effect of planting systems on the behavior oftwo cassava varieties regarding root rot incidence. It was observed that disease incidence is lower when cassava stakes are planted in ridges in comparison with planting in holes. The results also show that planting the susceptible local variety Cemitério in ridges, despite having both plant and roots infected by root rot pathogens, yielded the highest ro9t weight, l . 122 kglplant. Such a good behavior of Cemitério explains the cassava growers preference for this variety.Table5.4.2.3. Field evaluation of cassava hybrids, 1992 family, for resistance to root rot pathogens, in the municipality of Vi~osa, Sta te of Alagoas.In 1995 a high incidence of cassava root rot was observed in the rural community Chapada do Aporá, municipality of Aporá, State ofBahia. Two on-farm trials were installed in that rural community aiming at evaluating the behavior of cassava varieties and promising hybrids regarding root rot incidence. As shown in Table5.4.2.4, despite showing 45% infected plants and 15 .2% infected roots, the local variety Cemitério hada very good performance regarding to root yield, l . 44 kglplant, just behind Paraibana, that yielded l . 52 kg/plant , while Olho Verde showed the lowest root weight, only 0.285 kg/plant. As can be concluded from data in Table 5.4.4, root rot incidence was very low throughout the experiment, except for the local variety Cemitério. It is possible that the root rot incidence in Cemitério may be dueto the use of infected planting material rather than infection from contaminated soil. Breeding Program!PROFISMA joint activity. From 1986 to 1993 eight hundred and seventy Breeding Program!PROFISMA joint activity. From 1986 to 1993 eight hundred and seventy cassava clones from the EMBRAP A/CNPMF Cassava Breeding Program were tested, cassava clones from the EMBRAP A/CNPMF Cassava Breeding Program were tested, through farmer participatory methods, in the Serra da lbiapaba growing area, where there are through farmer participatory methods, in the Serra da lbiapaba growing area, where there are about 5,000 ha planted with cassava, most ofthem planted with the cassava variety Cruvela, about 5,000 ha planted with cassava, most ofthem planted with the cassava variety Cruvela, highly susceptible to the CWBD pathogen. After severa! years of evaluation, seven highly susceptible to the CWBD pathogen. After severa! years of evaluation, seven promising clones were selected. In 1994 these seven clones were then evaluated in promising clones were selected. In 1994 these seven clones were then evaluated in comparison with the local variety Cruvela, susceptible to the pathogen, and the CWBD comparison with the local variety Cruvela, susceptible to the pathogen, and the CWBD resistant variety Bujá, was recommended by the State ofCeará Agricultura! Research resistant variety Bujá, was recommended by the State ofCeará Agricultura! Research Institution (EPACE). On-farm trials were installed in 60 rural communities, located in seven Institution (EPACE). On-farm trials were installed in 60 rural communities, located in seven municipalities in the Serra de Ibiapaba cassava growing region. Evaluation at harvest time, municipalities in the Serra de Ibiapaba cassava growing region. Evaluation at harvest time, carried out by cassava growers in 53 rural communities enabled the selection of the clones carried out by cassava growers in 53 rural communities enabled the selection of the clones 8709-2 and 8911-16 for harvesting at both 12 and 18 months after planting, clone 8952-06 8709-2 and 8911-16 for harvesting at both 12 and 18 months after planting, clone 8952-06 only for harvesting at 18 months and clone 8 7 40-1 O for harvesting at 12 months after only for harvesting at 18 months and clone 8 7 40-1 O for harvesting at 12 months after planting. planting.  "},{"text":"Table 5 . 5.1. Land area of the surveyed cassava growers in Northeast Brazil.Total is higher than 1 00% because sorne growers ha ve are as in more than one land usage.  Average  Freguenc~  AverageFreguenc~ Laod extracts land area Absolut Relative Accumulated Laod extractsland areaAbsolutRelative Accumulated  {her} {number) {%) {%) {her}{number){%){%) Smaller than 5 her 1.9 150.0 53.4 53.4 Smaller than 5 her1.9150.053.453.4 Larger than 5 her, smaller than 1 O her 6.8 44.0 15.7 69.0 Larger than 5 her, smaller than 1 O her6.844.015.769.0 Larger than 1 O her, smaller than 20 ~er 12.6 45 .0 16.0 85.1 Larger than 1 O her, smaller than 20 ~er12.645 .016.085.1 Larger than 20 her, smaller than 30 her 24.4 13 .0 4 .6 89.7 Larger than 20 her, smaller than 30 her24.413 .04 .689.7 Larger than 30 her, smaller than 60 her 48.6 19.0 6.8 96.4 Larger than 30 her, smaller than 60 her48.619.06.896.4 Laq~er than 60 her, smaller than 90 her 72 .0 10.0 3.6 100.0 Laq~er than 60 her, smaller than 90 her72 .010.03.6100.0  "},{"text":"Table 5 .5.2. Land usage and average land area in each kind of use by cassava growers in Northeast Brazil.   Relative participation 1 Average land Relative participation 1Average land Land usage (%) area (her) Land usage(%)area (her) Either annual or perennial crops 100.0 3.9 Either annual or perennial crops100.03.9 Pasture 29.9 5.0 Pasture29.95.0 Fallow 29.9 7.4 Fallow29.97.4 Native vegetation 13 .2 10.2 Native vegetation13 .210.2 Forest 11.4 16.4 Forest11.416.4 Non productive area 9.6 0.7 Non productive area9.60.7  "},{"text":" ••    School educated Not school educated School educatedNot school educated Members Freguenc! {%} Number {%} Number {%} MembersFreguenc!{%}Number{%}Number{%} Head 3 18 15 .6 182 57.23 136 42.77 Head3 1815 .618257.2313642.77 Wife 301 14.7 196 62. 12 105 34.88 Wife30114.719662. 1210534.88 Daughter 674 33 .0 600 89.02 74 10.98 Daughter67433 .060089.027410.98 Son 687 33 .6 554 80.64 133 19.36 Son68733 .655480.6413319.36 Son in law 14 0.7 9 64.29 5 35 .71 Son in law140.7964.29535 .71 Sister 6 0.3 4 66.67 2 33 .33 Sister60.3466.67233 .33 Brother 4 0.2 4 100.0   Brother40.24100.0 Mother 12 0.6 5 41.67 7 58 .33 Mother120.6541.67758 .33 Granddaughter 6 0.3 3 50.00 3 50.00 Granddaughter60.3350.00350.00 Grandson 16 0.6 8 66.67 4 33 .33 Grandson160.6866.67433 .33 Daughter in law 5 0.2 2 40.00 3 60.00 Daughter in law50.2240.00360.00 Father  0.0     Father0.0 Cousin  0.0  100.00   Cousin0.0100.00 Niece 2 0. 1  50.00  50.00 Niece20. 150.0050.00 NeEhew  0.0  100.00   NeEhew0.0100.00  "},{"text":" Table5.5.4. Leafcutter ants have been considered a very important cassava pest in the last years, followed by CGM, homworm, whiteflies, and root rot. In general, cassava pests are responsible for around 22% decrease of root yield, except for witches' broom and root rot diseases that cause, respective! y, 71 .9% and 51.8% root yield losses. The stage of plant development at the time of pest/disease detection varíes from 1-3 month after planting for ants, and up to 12 months for root rot. ~hte  ~hte 13.0%  13.0%  Homwonn Homwonn  16.5% 16.5%  Others Others  5.8'/ . 5.8'/ .  3.2% 3.2% Root rot 8.2'/o Root rot8.2'/o 20.7%  20.7%  "},{"text":"Table 5 .5.4 Cassava pests and diseases in Nortbeast Brazil and their importance to tbe crop, according to growers.   Infection Infected organ (%) Period of Yield InfectionInfected organ (%)Period ofYield Pest/disease (%) Root Aerial part observation (year) loss (%) Pest/disease(%)RootAerial part observation (year) loss (%) Homwonn 16.5  98.3 15 22.7 Homwonn16.598.31522.7 Mi te 13.0  81.5 16 21.6 Mi te13.081.51621.6 Leaf-cutting 29.4  99.0 19 22.3 Leaf-cutting29.499.01922.3 ants     ants Root rot 20.7 99.3  11 51 .8 Root rot20.799.31151 .8 Whiteflies 8.2  96.6 13 22.9 Whiteflies8.296.61322.9 Witches ' broom 3.4  100.0 5 71.9 Witches ' broom3.4100.0571.9 Stake weevil 3.1  95 .5 7 33 .5 Stake weevil3.195 .5733 .5 Others 5.8    Others5.8  "},{"text":"Table 5 . 5.5. Control measures for pests and diseases used by cassava growers in Northeast Brazil. Pest Gro\"'en Klnd of    Month \"'hen control measures are a(!J!lied   PestGro\"'enKlnd ofMonth \"'hen control measures are a(!J!lied Disuse {%l Control  2 3 4 S 6 7 8 9 10 11 12 Disuse{%lControl234S6789101112 Mites 100 None            Mites100None Homwonn 50 Non e            Homwonn50Non e  so Chemical + + ++ ++ ++ ++    + + + soChemical+++++++++++++ Ants u non e            Antsunon e  98.5 chemical + ++ ++ ++ ++ ++ + +  +  98.5chemical++++++++++++++ Tennites lOO none            TenniteslOOnone Whiteflies lOO non e            WhiteflieslOOnon e Stake weevil lOO non e            Stake weevillOOnon e Anthracnose so non e            Anthracnosesonon e  so chemical + + ++ ...... ++ ......  +  + + sochemical++++......++......+++ Root rot so non e            Root rotsonon e  33.3 lime   ++ +- ++      + 33.3lime+++-+++  16.7 Ash +  +- ++ -+ ++  + + +  16.7Ash++-++-++++++ CWBD 100 non e            CWBD100non e  "},{"text":"Table 5 . 5.6. So urce of information regarding price of cassava products . ........................................................ f.. ~~~.!-: . ~~-~~ ..  "},{"text":" Table 5.5. 7. Destination of the cassava production in Northeast Brazil. 6 PARTICIPANTS AND INSTITUTIONS   6 PARTICIPANTS AND INSTITUTIONS Alba Rejane Nunes Farias  EMBRAP A/CNPMF Alba Rejane Nunes FariasEMBRAP A/CNPMF Alrnir Dias da Silva  IPA   Alrnir Dias da SilvaIPA Aloyséia Cristina da Silva Noronha EMBRAP A/CNPMF Aloyséia Cristina da Silva NoronhaEMBRAP A/CNPMF Ana Maria Mascarenhas Eloy Canto IICA/CNPMF   Ana Maria Mascarenhas Eloy CantoIICA/CNPMF Anthony Bellotti  CIAT   Anthony BellottiCIAT Antonio Mela  EMEPA   Antonio MelaEMEPA Antonio Rairnundo Cavalcante EMATERCE   Antonio Rairnundo CavalcanteEMATERCE Apoliano A. dos Santos  EPACE   Apoliano A. dos SantosEPACE Aristoteles Pires de Matos  EMBRAP A/CNPMF Aristoteles Pires de MatosEMBRAP A/CNPMF Arlinda Pereira Eloy  CNPq/CNPMF   Arlinda Pereira EloyCNPq/CNPMF Bernardo Ospina Patiño  CIAT   Bernardo Ospina PatiñoCIAT Source of information Célia Carnara do Vale Chi~s {%) Flour {%) IICA/CNPMF /UFC Starch {%) Fresh root {%) Source of information Célia Carnara do ValeChi~s {%)Flour {%) IICA/CNPMF /UFC Starch {%) Fresh root {%) Growers association Chigeru Fukuda 2.5 1.4 EMBRAP A/CNPMF 1.1 2.5 Growers association Chigeru Fukuda2.51.4 EMBRAP A/CNPMF 1.12.5 Extension worker Other grower Cícero T. C. Pereira 6.8 3.6 8.2 31.3 EMATERCE 4.3 9.6 7.8 17.4 Extension worker Other grower Cícero T. C. Pereira6.8 3.68.2 31.3 EMATERCE4.3 9.67.8 17.4 Wholesaler Cláudio Luiz Messias l.l 31.3 UNICAMP 10.7 24 .9 Wholesaler Cláudio Luiz Messiasl.l31.3 UNICAMP10.724 .9 Radio Cláudio Jonsson 1.4 6.0 EMBRAP A/CNPMA 1.1 1.8 Radio Cláudio Jonsson1.46.0 EMBRAP A/CNPMA 1.11.8 Newspaper/TV 1.1 1.4 0.0 0.7 Newspaper/TV1.11.40.00.7 Local market Edna Castilho Leal 2.5 64.8 EMBRAPA/CPATC 12. 1 17.4 Local market Edna Castilho Leal2.564.8 EMBRAPA/CPATC 12. 117.4 Non e Edson Mathias 0.4 1.4 EMEPA 1. 1 0.4 Non e Edson Mathias0.41.4 EMEPA1. 10.4 Elizabeth Alvarez  CIAT   Elizabeth AlvarezCIAT El ton de O . dos Santos  IPA   El ton de O . dos SantosIPA Destination   Percentage DestinationPercentage Sell as fresh root Fernando Gallindo  IPA 19. 1 Sell as fresh root Fernando GallindoIPA19. 1 Cassava flour Francisco de Assis Paiva Ca,pos IPA 76.8 Cassava flour Francisco de Assis Paiva Ca,posIPA76.8 Chips Animal feeding Genário Marcolino Queiroz EPACE 0.7 1.6 Chips Animal feeding Genário Marcolino QueirozEPACE0.7 1.6 Others Gilbert J. de Moraes  EMBRAP A/CNPMA 1.8 Others Gilbert J. de MoraesEMBRAP A/CNPMA1.8 Henrique A. Lima  EMATERCE   Henrique A. LimaEMATERCE !talo Delalibera Juniorr  IICA/CNPMF   !talo Delalibera JuniorrIICA/CNPMF  "}],"sieverID":"9b4e2f32-7f6c-43e3-895c-306c4ae9ecde","abstract":"PROFISMA completed its fourth project year at the close of 1996, thus terminating GL0/91/013 . The project has made notable progress in basic and applied research in biological control, integrated pest management and integrated crop management in cassava, emphasizing participation of farmers in Northeast Brazil in the identification of high priority problems and the development and evaluation of technological solutions."}
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