Pests and Diseases
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Item Optimizing the Timing of Management Interventions Against Fall Armyworm in African Smallholder Maize: Modelling the Pattern of Larval Population Emergence and Development(Elsevier Ltd., 2022-03-25) Lowry, A.; Durocher-Granger, L.; Oronje, M.L.; Mutisya, D.; Mfune, T.; Gitonga, C.; Musesha, M.; Taylor, B.; Wood, S.; Chacha, D.; Beale, T.; Finch, E.A.; Murphy, S.T.; CABI ; Kenya Agricultural and Livestock Research Organisation (KALRO) ; Zambia Agriculture Research Institute (ZARI)Since its invasion in late 2016, the fall armyworm has a widespread year-round distribution within Africa where it continues to threaten cereal production, particularly maize. Most recommended control advice emphasises the need for interventions against larvae early after colonization of a new maize crop by adults followed by a later intervention if an infestation persists. The current times for action are approximate action thresholds based on scouting which are difficult to implement as early development stages are cryptic and farmers, especially smallholders, have limited time for crop assessments. To improve the impact of controls, the modelling of early and late instar larval population emergence and development in relation to physiological time from planting was developed to enable times to action to be predicted and conveyed to farmers. The two larval population emergence models were built from field fall armyworm data from maize in Zambia and validated from similar data from multiple maize sites in Kenya. A component was included in the models to allow synchronization of maize emergence with larval development. Physiological time, in degree-days, was estimated using Earth Observation land surface temperature data sets. As precise information on action thresholds is lacking for Africa, recent published data on thresholds based on economic injury levels from Colombia were used as a guide but the models can be updated when new information becomes available for Africa. The practical implementation of the models in Africa is discussed including the outcome of some recent preliminary trials with maize farmers in Kenya.Item Relative Yield Loss of Potato in Fields Infested with Potato Cyst Nematodes and the Efficacy of Selected Control Products in Nyandarua County, Kenya(East African Agricultural and Forestry Journal, 2022-12-15) Mbiyu, M.W.; Kimenju, J.W.; Muiru, W.M.; Nyongesa, M.W.; Haukeland, S.; University of Nairobi ; Kenya Agricultural Livestock Research Organization ; International Centre of Insect Physiology and Ecology (icipe) ; The Norwegian Institute of Bioeconomy Research (NIBIO)Despite the rapid spread of potato cyst nematodes (PCN) in Kenya, data on associated yield loss is limited. The objective of this study was to determine the efficacy of four nematicides and relative yield loss associated with PCN damage. Three on-farm sites with varying PCN densities (low; 1-9, moderate; 10-39, and high; 40-80 cysts in 100 g/soil) were selected for the study in Nyandarua County during the 2021 long and short rains seasons. Treatments consisted of three potato cultivars namely Desiree and Shangi (susceptible) and Manitou, which is partially resistant. The four PCN control products tested were, fluopyram, oxamyl, azandirachtin (commercial neem extract) and Paecilomyces lilacinus. The experiments were set up in a randomized complete block design, in a split plot arrangement, with varieties as the main plots, and PCN control products including the control as the sub-plots. Treatments were replicated three times. The reproductive index of the nematodes ranged from 0.17 to 2.39 during the long rains and from 0 to 4.13 during the short rains season. Relative yield loss attributed to PCN infection varied from 6.3% to 80.5% during the long rain season and from 5.5% to 73.3% during the short rain season. The magnitude of yield losses was dependent on susceptibility of the variety and the initial PCN population density. This study has demonstrated that PCN are already causing substantial yield losses especially in heavily and moderately infested fields. The study demonstrated that oxamyl was the most effective nematicide in reducing PCN numbers and yield losses. Farmers are advised to take appropriate measures to prevent spread and buildup of the nematodes.Item Assessment of Pesticide Multiplicity in Potato Production and Storage in Bomet, Kenya(East African Agricultural and Forestry Journal, 2022-06-02) Oyoo, J.I.; Abong, G.O.; Okoth, M.W.; Nyongesa, M.W.; Kenya Agricultural and Livestock Research Organization ; University of NairobiPotato (Solanum tuberosum L.) crisps are among the most appealing potato products to middle and high income households including women, youth and children and are produced from potatoes mainly grown in Bomet County. A cross-sectional survey was done in 305 potato growing households in Bomet County to establish categories of pesticides used in potato production and storage, level of awareness of pesticide residues and perceptions of risks associated with pesticide contamination at ingestion of potato and its products. Questionnaires were administered through simple random sampling of potato farmers, disaggregated according to their gender, level of education and age. The parameters of interest were type of pesticides applied, knowledge of banned or restricted pesticides and knowledge of presence of pesticide residues in potatoes and risks involved. Data was collected using open data kit (ODK) and analysis done using Statistical Package for Social Science (SPSS) software version 21. Descriptive statistics were used to generate socio-demographic characteristics (gender, age, education levels) and analysis of variance (ANOVA) was performed on the data about knowledge of pesticides. Results are presented as percentages, means and frequency distribution. Differences between the means were calculated at 95% level of significance using Fischer’s test. The study showed that 72% of the respondents were male and 28% female. Most of the potato farmers aged between 20- 59 years (87.2%). A majority of the sampled farmers (26.9%) had up to tertiary level education while 31% attended primary school only. About 95% of the respondents used fungicides to control late blight while 14% used insecticides for pest control. It is worth noting that only 0.6% of the respondents used dimethoate and Diazinon, restricted/banned chemical compounds in Kenya. A significant number of fungicides (47%) used were classification class II which are moderately hazardous. Most respondents (79%) could not tell which pesticides had high residues. However, majority (84%) perceived that potatoes in the markets or those cooked at home, restaurants or hotels contained pesticide residues which could harm consumers. The study demonstrated the need for more awareness creation on appropriate pesticide use and sensitization on pesticide residues in potato production.Item Field Margins and Cropping System Influence Diversity and Abundance of Aphid Natural Enemies in Lablab purpureus(Wiley-VCH GmbH., 2023-05-10) Obanyi, J.N.; Ogendo, J.O.; Mulwa, R.M.S.; Nyaanga, J.G.; Cheruiyot, E.K.; Bett, P.K.; Belmain, S.R.; Arnold, S.E.J.; Nash-Woolley , V.C.; Stevenson, P.C.; Egerton University ; University of Greenwich ; NIAB East Malling ; Crop Health & Protection Limited ; Royal Botanic GardensField margin plants around crops are postulated to increase natural enemy abundance to enhance pest management. A trial was conducted to determine the contribution of field margin vegetation and cropping systems to natural enemies of bean aphids (Aphis fabae) on Lablab purpureus, an orphan crop legume. Natural enemy populations were surveyed in plots with a combination of lablab monocrop or maize‐lablab intercrop and with or without planted field margins comprising four plant species (Chenopodium album, Bidens pilosa, Galinsoga parviflora and Tagetes minuta), arranged in a randomized complete block design with four replicates. A cage experiment was also conducted to understand the extent to which these field margin plants supported the parasitoid wasp, Aphidius colemani, to parasitize bean aphids. A total of 2029 insects from 10 families were collected using sticky cards and pan traps. In comparison to plots with no field margin plants, the presence of plant‐rich field margins increased abundance of natural enemies by 9.5% and supported higher populations of Braconidae (parasitoids) and damsel bugs (predators). The maize‐lablab intercrop had 15.5% lower abundance of natural enemies than the lablab monocrop. Higher grain yield was recorded in plots with a field margin vegetation (300 kg ha−1) compared to plots without field margin vegetation (210 kg ha−1). The presence of a companion plant did not significantly affect the performance of parasitoids, in the cage experiment, indicating that parasitoids were not limited by access to food. In supporting aphid parasitization, B. pilosa was associated with the highest number of mummies (8.28). The lowest number of mummies were observed in cages with T. minuta (3.44). These results demonstrate the potential of plant‐rich field margins to augment natural enemy populations and enhance conservation biocontrol of aphids.Item First Report of Ethiopian Tobacco Bushy Top Virus and Its Associated Satellite RNA in Mixed Infection with Potato Virus Y Affecting Solanum betacea in Kenya(British Society for Plant Pathology and John Wiley & Sons, 2021) Kinoga, M.N.; Kuria, P.K.; Miano, D.W.; Narla, R.D.; Wasilwa, L.A.; Kenya Agricultural and Livestock Research Organization ; University of NairobiVirus-associated symptoms including leaf malformation, curling and vein banding, mosaics, yellowing, mottling were observed in tree tomato (Solanum betacea) farms in Kenya. A survey was conducted in four counties (Machakos, Embu, Tharaka Nithi and Meru) and 142 leaf samples showing virus-associated symptoms were collected from 14 farms.Item First Report of Potato Spindle Tuber Viroid Infecting Tree Tomato in Kenya: Coinfection with Potato Virus Y(Wiley, 2021) Kinoga, M.N.; Kuria, P.K.; Miano, D.W.; Wasilwa, L.A.; Kenya Agricultural and Livestock Research Organization ; University of NairobiThe article discusses a 2021 report on the infection of tree tomato in Kenya by a mix of Potato spindle tuberviroid (PSTVd) and Potato virus Y (PVY). It states that infected trees have the symptoms of leaf mottling and malformation, and veinal necrosis. Also noted is the need for further study if PSTVd affects tree tomato yield, and to identify its other reservoir hosts.Item Efficacy of Botanical Extract Formulations of Zanthroxylum Usambarense and Warburgia Ugandensis on Post-Harvest Management of Sitophilus Zeamais in Maize(MDPI, 2023-07-10) Mpoke, R.S.; Kinyua, J.; Kimani, J.W.; Ajene, I.J.; Likhayo, P.; Khamis, F.M.; International Centre of Insect Physiology and Ecology (icipe) ; Jomo Kenyatta University of Agriculture and Technology ; Kenya Agricultural and Livestock Research Organization (KALRO)Sitophilus zeamais causes significant losses to maize produce worldwide. The use of biodegradable and environmentally friendly botanicals as an alternative to synthetic pesticides is increasingly becoming important. Therefore, we sought to determine the use of plant extract formulations to manage S. zeamais during storage. Crude Zanthroxylum usambarense and Warburgia ugandensis stembark extracts were used for contact toxicity and repellent bioassays against S. zeamais. The formulations that exhibited the highest repellence and mortality were tested for insecticidal activity during storage for six months. Phytochemical profiles of the extracts were determined using GC-MS, and molecular docking of active compounds against insect target proteins was done. Mortality analyses revealed LD50 values of 114.89 μg/mL and 197.19 μg/mL for Z. usambarense’s hexane and methanol organic extracts, respectively. Warburgia ugandensis extracts had LD50 values of 69.25 μg/mL and 163.52 μg/mL, respectively. Extract formulations achieved weevil perforation index values of <50.00 in all treatments. The docking analysis showed the pesticidal potential of several compounds, and mortality could be attributed to Eugenol (19.28%), 1,8-cineole (5.78%) and Linalool (21.42%). The tested botanicals have demonstrated their ability to suppress S. zeamais development in stored maize and could be utilized to protect maize grains during storage.Item Characterization and Pathogenicity Test of Entomopathogenic Nematode Steinernema Species-Kalro(Canadian Center of Science and Education, 2021-02-15) Ngugi, C.N.; Wachira, P.M.; Mbaka, J.N.; Okoth, S.; Haukeland, S.; Mburu, H.M.; Adhiambo, M.; Sirengo, D.K.; Kenya Agricultural and Livestock Research Organisation ; University of Nairobi ; International Center of Insect Physiology and EcologyEntomopathogenic nematodes (EPNs) are worldwide soil-dwelling insect parasitic nematodes. They are potential pest bio-control agents a key component of Integrated Pest Management (IPM) programs. This study aimed to characterize and evaluate the pathogenicity of an EPN isolate from Kenya. The nematode was isolated from soils using insect bait technique and both morphological and molecular identification was performed. Efficacy of the isolate was evaluated against Tomato leafminer larvae (Tuta absoluta Meyrick.) using dose-based treatments of 0-control, 100, 150, 200, and 250 infective juveniles (IJs/ml). Morphological analysis revealed body length (L) of 835(659-987) µm and 1781 (1297-2097) µm from fresh IJs and males respectively. Males lacked a mucron. The isolate was characterized by the partial sequence length of 877 bp of the ITS region. Blastn results indicated the EPN isolate had a similarity match of 81-92% with Afro-tropical Steinernema species. It matched with Steinernema sp. (AY230186.1) from Kenya at 92% and Sri Lanka (AY230184.1). Phylogenetic analysis placed the isolate together with Steinernema sp. (AY230186.1) and (AY230184.1) with a bootstrap value of 100%. Maximum mean larval mortality (80%; 96%) was achieved 24 and 48 h post-treatment at concentration 150 IJs/ml. All nematode concentrations achieved over 50% mean mortality after 24 h period. There was a significant difference (P = 0.001) between doses 150 and 200 IJs/ml. From the study, it was concluded that the nematode isolate was Steinernema sp now referred to as Steinernema sp. Kalro (Genebank Accession MW151701). The EPN has the potential for development as a biological control agent against T. absoluta.Item Characterization and Pathogenicity of Symbiotic Bacteria Associated with Entomopathogenic Nematode: Steinernema Species KALRO(East African Journal of Science, Technology and Innovation, 2021-09-25) Ngugi, C.N.; Wachira, P.M.; Mbaka, J.N.; Okoth, S.; Mangua, P.W.; Kenya Agricultural and Livestock Research Organization (KALRO) ; University of NairobiThe soil inhibiting entomopathogenic nematodes (EPNs), in the family Steinernematidae and Heterorhabditidae, are useful insect biological control agents. They have been used in the management of economically important crop pests. The EPNs are mutually associated with symbiotic bacteria genus Xenorhabdus and Photoharbdus respectively. The study aimed to isolate, characterize and evaluate the pathogenicity of symbiotic bacteria associated with EPN Steinernema sp. Kalro (Accession MW151701). The EPN Steinernema sp. Karlo was multiplied using the insect baiting technique. Its bacteria symbiont was isolated and characterized based on microscopic, biochemical, and physiological features like Gram staining, urease, motility test, and glucose fermentation test). Molecular identification and phylogenetic analysis were performed on 16S rDNA nucleotide sequence. Pathogenicity of the bacteria isolate was evaluated against Tuta absoluta larvae with mortality data recorded after 24 and 48hours of exposure to the bacterial cell suspension. The bacteria were found to be motile and glucose fermentation positive. Sequence analysis of 16S rDNA region resulted in 1500bp sequence with maximum similarity of between 97 and 98.93%, with Xenorhabdus spp Accessions from Genbank. It closely matched to Xenorhabdus sp. My8NJ with 98.93% similarity (Accession AB507811.1). Mean percent larval mortality of 68±4.9 and 88±8.0 in the lowest cell suspension was observed in 24 and 48h of exposure. It’s concluded that, the symbiotic bacteria associated with Steinernema sp. Kalro is Xenorhabdus sp. strain Kalro Genbank Accession MW245845. The bacteria is a potential biological control agent against Tuta absoluta larvae. Further classification of the bacteria to species level and pathogenicity trials in the screen house and field are recommended.Item Interactions Between Integrated Pest Management, Pollinator Supplementation, and Normalized Difference Vegetation Index in Pumpkin, Cucurbita Maxima (Cucurbitales: Cucurbitaceae), Production(Oxford University Press, 2023-05-12) Waithaka, N.A.; Kasina, M.; Samita, N.E.; Guantai, M.M.; Omuse, E.R.; Toukem, N.K.; Lattorf, M.G.; Abdel-Rahman, E.M.; Adan, M.; Mohamed, S.A.; Dubois, T.; Kenyatta University ; Kenya Agricultural and Livestock Research Organization (KALRO) ; Kenya Plant Health Inspectorate Service (KEPHIS) ; International Centre for Insect Physiology and Ecology (icipe) ; University of Pretoria ; University of NairobiSustainable production of pumpkin (Cucurbita maxima Duchesne) partly relies on integrated pest management (IPM) and pollination services. A farmer-managed field study was carried out in Yatta and Masinga Sub-Counties of Machakos County, Kenya, to determine the effectiveness of a recommended IPM package and its interaction with stingless bee colonies (Hypotrigona sp.) for pollinator supplementation (PS). The IPM package comprised Lynfield traps with cuelure laced with the organophosphate malathion, sprays of Metarhizium anisopliae (Mechnikoff) Sorokin isolate ICIPE 69, the most widely used fungal biopesticide in sub-Saharan Africa, and protein baits incorporating spinosad. Four treatments—IPM, PS, integrated pest and pollinator management (which combined IPM and PS), and control—were replicated 4 times. The experiment was conducted in 600 m2 farms in 2 normalized difference vegetation index (NDVI) classes during 2 growing seasons (October 2019–March 2020 and March–July 2020). Fruits showing signs of infestation were incubated for emergence, fruit fly trap catches were counted weekly, and physiologically mature fruits were harvested. There was no effect of IPM, PS, and NDVI on yield across seasons. This study revealed no synergistic effect between IPM and PS in suppressing Tephritid fruit fly population densities and damage. Hypotrigona sp. is not an efficient pollinator of pumpkin. Therefore, we recommend testing other African stingless bees in pumpkin production systems for better pollination services and improved yields.Item Genomes of the Cosmopolitan Fruit Pest Bactrocera Dorsalis (Diptera: Tephritidae) Reveal its Global Invasion History and Thermal Adaptation(Elsevier B.V., 2023-11) Zhang, Y.; Liu, S.; de Meyer, M.; Liao, Z.; Zhao, Y.; Virgilio, M.; Feng, S.; Qin, Y.; Singh, S.; Wee, S.K.; Jiang, F.; Guo, S.; Li, H.; Deschepper, P.; Vanbergen, S.; Delatte, H.; van Sauers-Muller, A.; Syamsudin, T.S.; Kawi, A.P.; Kasina, M.; Badji, K.; Said, F.; Liu, L.; Zhao, Z.; Li, Z.; China Agricultural University ; Ministry of Agriculture and Rural Affairs ; Royal Museum for Central Africa ; Punjab Agricultural University ; University Kebangsaan Malaysia ; Chinese Academy of Inspection and Quarantine ; CIRAD UMR PVBM ; Ministry of Agriculture ; Bandung Institute of Technology ; Port Moresby ; Apiculture Research Institute ; Crop Protection Directorate ; Abdul Wali Khan University MardanIntroduction. The oriental fruit fly Bactrocera dorsalis is one of the most destructive agricultural pests worldwide, with highly debated species delimitation, origin, and global spread routes. Objectives. Our study intended to (i) resolve the taxonomic uncertainties between B. dorsalis and B. carambolae, (ii) reveal the population structure and global invasion routes of B. dorsalis across Asia, Africa, and Oceania, and (iii) identify genomic regions that are responsible for the thermal adaptation of B. dorsalis. Methods. Based on a high-quality chromosome-level reference genome assembly, we explored the population relationship using a genome-scale single nucleotide polymorphism dataset generated from the resequencing data of 487 B. dorsalis genomes and 25 B. carambolae genomes. Genome-wide association studies and silencing using RNA interference were used to identify and verify the candidate genes associated with extreme thermal stress. Results. We showed that B. dorsalis originates from the Southern India region with three independent invasion and spread routes worldwide: (i) from Northern India to Northern Southeast Asia, then to Southern Southeast Asia; (ii) from Northern India to Northern Southeast Asian, then to China and Hawaii; and (iii) from Southern India toward the African mainland, then to Madagascar, which is mainly facilitated by human activities including trade and immigration. Twenty-seven genes were identified by a genome-wide association study to be associated with 11 temperature bioclimatic variables. The Cyp6a9 gene may enhance the thermal adaptation of B. dorsalis and thus boost its invasion, which tended to be upregulated at a hardening temperature of 38 °C. Functional verification using RNA interference silencing against Cyp6a9, led to the specific decrease in Cyp6a9 expression, reducing the survival rate of dsRNA-feeding larvae exposed to extreme thermal stress of 45 °C after heat hardening treatments in B. dorsalis. Conclusion. This study provides insights into the evolutionary history and genetic basis of temperature adaptation in B. dorsalis.Item Detection of the Spotted Wing Drosophila, Drosophila suzukii, in Continental Sub-Saharan Africa(Springer, 2021-01-23) Kwadha, C.A.; Okwaro, L.A.; Kleman, I.; Rehermann, G.; Revadi, S.; Ndlela, S.; Khamis, F.M.; Nderitu, P.W.; Kasina, M.; George, M.K.; Kithusi, G.G.; Mohamed, S.A.; Lattorff, H.M.G.; Becher, P.G.; Swedish University of Agricultural Sciences ; International Centre of Insect Physiology and Ecology ; Kenya Agricultural and Livestock Research Organisation ; KEPHIS Headquarters ; Horticultural Crops Directorate (HCD)The spotted wing drosophila, Drosophila suzukii Matsumura, is an insect pest of soft-skinned fruit, native to Eastern Asia. Since 2008, a world-wide dispersal of D. suzukii is seen, characterized by the establishment of the pest in many Asian, American and European countries. While the potential for invasion of continental Africa by D. suzukii has been predicted, its presence has only been shown for Morocco in Northern Africa. Knowledge about a possible establishment in other parts of the continent is needed as a basis for pest management. In 2019, we carried out a first survey in three counties in Kenya to monitor for the presence of D. suzukii using traps baited with a blend of apple cider vinegar and red wine. A total of 389 D. suzukii flies were captured in a fruit farm at Nakuru county, with more female flies being trapped than males. We confirmed the morphological identification of D. suzukii using DNA barcoding. In 2020, we performed a follow-up survey at 14 locations in six counties to delimit the distribution of D. suzukii in the main berry growing zones in Kenya. The survey indicated that so far D. suzukii is restricted to Nakuru county where it was initially detected. This is the first study to provide empirical evidence of D. suzukii in continental sub-Saharan Africa, confirming that the pest is expanding its geographic range intercontinentally. Given the high dispersal potential of D. suzukii, a concerted effort to develop management strategies is a necessity for containment of the pest.Item KARI/ODA Crop protection Project Farming System Survey Report(Kenya Agricultural Research Institute, 1992) Kenya Agricultural Research InstituteThis is the first nationwide Farming systems Survey (FSS) of Kenyan smallholder farmers' perceptions, particularly those relating to crop protection issues. The implementation and results of the survey meet a mixture of objectives set by the main KARI/ODA crop Protection project (cPP). The planning, testing, discussions, fieldwork interviews of 2107 farmers, data coding and input were all done with the training and involvement of KARl personnel, as this was part of a much wider strategy to help KARl's institutional strengthening. The analysis and publication of these results helps a related strategy - that of contributing to the process of prioritorising the KARI/ODA CPP's main research objectives. Some results relating to this objective have already been released in the Report on the crop Protection and FSS workshop, April 1992~ and this report does not aim to duplicate those results.Item Review of Kenyan Agricultural Research Vol. 30 Plant Diseases(Kenya Agricultural Research Institute, 1996) Kenya Agricultural Research Institute; Kedera, J.These reviews have been produced as part of the Kenyan Agricultural Research Database Project which was funded by the Netherlands government over the years 1992 to 1995. The aim of the project was to document all investigations and research related to agriculture in Kenya undertaken since the end of the last century, especially those items which had not been published. The computerized database now contains around 40,000 records, most of which contain abstracts or summaries, full bibliographic details, and information about where the documents can be found. We are conscious however, that many items have not yet been included especially the earlier material and many consultancy reports produced by foreign and international donor, development, and research organizations. Specialists who read the reviews may be aware of important topics which have been omitted by the reviewer. If this is be case, we would ask that both the reviewer and KARI's Library and Information Services be informed so that the topic can be included in future revisions. Constant up-date will be required as new research information becomes available with the National Agricultural Research System in Kenya.Item Review of Kenyan Agricultural Research Vol. 29 Pests of Plants(Kenya Agricultural Research Institute, 1996) Kenya Agricultural Research Institute; Mailu, A.M.These reviews have been produced as part of the Kenyan Agricultural Research Database Project which was funded by the Netherlands government over the years 1992 to 1995. The aim of the project was to document all investigations and research related to agriculture in Kenya undertaken since the end of the last century, especially those items which had not been published. The computerized database now contains around 40,000 records, most of which contain abstracts or summaries, full bibliographic details, and information about where the documents can be found. We are conscious however, that many items have not yet been included especially the earlier material and many consultancy reports produced by foreign and international donor, development, and research organizations. Specialists who read the reviews may be aware of important topics which have been omitted by the reviewer. If this is be case, we would ask that both the reviewer and KARI's Library and Information Services be informed so that the topic can be included in future revisions. Constant up-date will be required as new research information becomes available with the National Agricultural Research System in Kenya.Item Review Of kenyan Agricultural Research Vol.11 Post Harvest Technology(Kenya Agricultural Research Institute, 1996) Wongo. L.E.; Kenya Agricultural Research InstituteThese reviews have been produced as part of the Kenya Agricultural Research Database Project which was funded by the Netherlands government over the years 1992 to 1995. The aim of the project was to document all investigations and research related to agriculture in Kenya undertaken since the end of the last century, especially those items which had not been published. The computerised database now contains around 40,000 records, most of which contain abstracts or summaries, full bibliographic details, and information about where the documents can be found. We are conscious, however, that many items have not yet been included, especially the earlier material and many consultancy reports produced by foreign and international donors, development, and research organizations. Specialists who read the reviews may be aware of important topics which the reviewer has omitted. If this is the case, we would ask that both the reviewer and KARl's Library and Information Services be informed so that the topic can be included in future revisions. Constant up-date will be required as new research information becomes available with the National Agricultural Research System in Kenya.Item Know And Control Cassava Mealybug(Kenya Agricultural Research Institute, 1990) Kenya Agricultural Research InstituteCassava mealybug (CM) (Phenacoccus manihoti) was accidentally introduced into Africa in the early 1970s, most probably from South America, the original home of the cassava plant. Currently, this pest is found in most of the cassava growing belt in Sub-Saharan Africa, extending from 15°N to 200 S. Until recently, Kenya was one of the lucky few countries of the African cassava belt into which the pest had not spread.Item Survey of the Kari Bacterial Wilt of potatoes cause by Ralstonia solanacearum and its spread in the major potato growing areas of Kenya: Task Force Report to the Director-KARI(Kenya Agriculture Research Institute, 2007) Otipa, M.J.; Wakahiu, M.W.; Kinyae, P.M.; Thuo, D.N.; Kinoti, J.I.; Kenya Agriculture Research InstituteA survey conducted in all major potato-growing areas of Nakuru, Bomet, Nyandarua, Meru, and Nyeri districts showed that bacterial wilt continues to ravage the potato crop reducing yield and shelf life of harvested tubers. Generally, an average of between 30- 70% bacterial wilt incidences were observed. Comprehensive multidisciplinary control strategies need to be implemented to ensure this crop's continued growth, which is important in offering food security, alleviation of poverty, and generation of employment pportunities to the majority of Kenyans.Item The Occurance of Viruses and Aphid Vectors in Small Scale Potato Seed Production System and Their Effect on Yield Kenya(Machangi Joseph Maina, 2003) Maina, M.J.The overall objective of this study was to determine the incidence and distribution of Potato viruses, relationship to aphid vector population and effect of these vims diseases on yield loss and seed quality of different potato varieties in Kenya. The study was carried out in 3 phases, which were a field survey, on-farm monitoring and an on-station experiment on aphids and viruses.Item Use of Electrophoresis and activity of Peroxidases in Selection of Potato (Solanum Tuberosum) Clones Resistant to Late Blight (Phytophthora Infestans)(Kenya Agricultural Research Institiute, 1979) Nyachae, F.O.; Kenya Agricultural Research InstitiuteUse of electrophoresis of leaf peroxidase isozymes in selecting potato clones resistant to Phytophthora infestans was studied. The relationship between leaf peroxidase activity and foliar resistance to P. infestans as well as the effect of inoculation on pattern and activity of peroxidases were also investigated. The purpose of the study was to look into the possibility of using a rapid biochemical method of selecting potato clones resistant to the most serious potato disease, P. infestans.
