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International Centre of Insect Physiology and Ecology

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Articles 301 - 330 of 443

Full-Text Articles in Agricultural Science

Microclimate Modification And Insect Pest Exclusion Using Agronet Improve Pod Yield And Quality Of French Bean, Elisha Otieno Gogo, Mwanarusi Saidi, Jacob Mugwa Ochieng, Thibaud Martin, Vance Baird, Mathieu Ngouajio Oct 2014

Microclimate Modification And Insect Pest Exclusion Using Agronet Improve Pod Yield And Quality Of French Bean, Elisha Otieno Gogo, Mwanarusi Saidi, Jacob Mugwa Ochieng, Thibaud Martin, Vance Baird, Mathieu Ngouajio

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French bean [Phaseolus vulgaris (L.)] is among the leading export vegetable in Africa, mostly produced by small-scale farmers. Unfavorable environmental conditions and heavy infestations by insect pests are among the major constraints limiting production of the crop. Most French bean producers grow their crop in open fields outdoors subject to harsh environmental conditions and repeatedly spray insecticides in a bid to realize high yield. This has led to rejection of some of the produce at the export market as a result of stringent limits on maximum residue levels. Two trials were conducted at the Horticulture Research and Teaching Field, Egerton …

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Pesticide Risks From Fruit And Vegetable Pest Management By Small Farmers In Sub-Saharan Africa. A Review, Hubert De Bon, Joël Huat, Laurent Parrot, Antonio Sinzogan, Thibaud Martin, Eric Malézieux, Jean François Vayssières Sep 2014

Pesticide Risks From Fruit And Vegetable Pest Management By Small Farmers In Sub-Saharan Africa. A Review, Hubert De Bon, Joël Huat, Laurent Parrot, Antonio Sinzogan, Thibaud Martin, Eric Malézieux, Jean François Vayssières

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Chemical control has highly expanded over the last 30 years in sub-Saharan Africa to reduce bio-aggressors on all crops. Pest management of fruits and vegetables by small farmers in sub-Saharan Africa have developed anarchically in a fuzzy regulation framework. Pesticide toxicity and excessive application are often criticized both by farmers and consumers. Here, we review pesticide management in sub-Saharan Africa over the past 30 years. We then propose options to improve and reduce pesticide application, in order to decrease environmental and human hazards. The major points are as follows: (1) global changes in sub-Saharan Africa such as urbanization modify farmer …

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Effects Of The Invasive Tomato Red Spider Mite (Acari: Tetranychidae) On Growth And Leaf Yield Of African Nightshades, Lucy K. Murungi, Daisy Salifu, Peter Masinde, John Wesonga, Aggrey Nyende, Markus Knapp May 2014

Effects Of The Invasive Tomato Red Spider Mite (Acari: Tetranychidae) On Growth And Leaf Yield Of African Nightshades, Lucy K. Murungi, Daisy Salifu, Peter Masinde, John Wesonga, Aggrey Nyende, Markus Knapp

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The tomato red spider mite, Tetranychus evansi Baker and Pritchard, is one of the most serious pests of solanaceous crops in Africa. Field experiments were conducted to investigate its effects on the growth and leaf yield of five African nightshade species viz. Solanum americanum, S. sarrachoides, S. scabrum, S.tarderemotum and S. villosum during the 2008 and 2009 growing seasons. Plants were infested with 2-4 day-old female spider mites which were allowed to multiply. The number of mite motiles increased throughout the growing season in unsprayed plots and this number varied significantly between the African nightshade species. Except for S.sarrachoides, leaf …

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Effects Of Landscape Complexity And Habitat Management On Stemborer Colonization, Parasitism And Damage To Maize, Charles A.O. Midega, Mattias Jonsson, Zeyaur R. Khan, Barbara Ekbom Apr 2014

Effects Of Landscape Complexity And Habitat Management On Stemborer Colonization, Parasitism And Damage To Maize, Charles A.O. Midega, Mattias Jonsson, Zeyaur R. Khan, Barbara Ekbom

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Lepidopteran stemborers are a serious constraint to efficient production of maize in sub-Saharan Africa. One of the most effective ways of managing these pests is through a habitat management system called push-pull. Landscape complexity has been shown to enhance biological control of insect pests, and therefore may influence effectiveness of habitat management systems designed to control pests. We studied the relative importance of the push-pull cropping system as a local effect and proportional cover of grassland as a landscape effect on (i) stemborer population density and damage to maize, and (ii) parasitism and mortality of stemborer life stages in western …

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Push-Pull Farming Systems, John A. Pickett, Christine M. Woodcock, Charles A.O. Midega, Zeyaur R. Khan Apr 2014

Push-Pull Farming Systems, John A. Pickett, Christine M. Woodcock, Charles A.O. Midega, Zeyaur R. Khan

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Farming systems for pest control, based on the stimulo-deterrent diversionary strategy or push-pull system, have become an important target for sustainable intensification of food production. A prominent example is push-pull developed in sub-Saharan Africa using a combination of companion plants delivering semiochemicals, as plant secondary metabolites, for smallholder farming cereal production, initially against lepidopterous stem borers. Opportunities are being developed for other regions and farming ecosystems. New semiochemical tools and delivery systems, including GM, are being incorporated to exploit further opportunities for mainstream arable farming systems. By delivering the push and pull effects as secondary metabolites, for example, (E)-4,8-dimethyl-1,3,7-nonatriene repelling …

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Development And Assessment Of Plant-Based Synthetic Odor Baits For Surveillance And Control Of Malaria Vectors, Vincent O. Nyasembe, David P. Tchouassi, Hillary K. Kirwa, Woodbridge A. Foster, Peter E.A. Teal, Christian Borgemeister, Baldwyn Torto Feb 2014

Development And Assessment Of Plant-Based Synthetic Odor Baits For Surveillance And Control Of Malaria Vectors, Vincent O. Nyasembe, David P. Tchouassi, Hillary K. Kirwa, Woodbridge A. Foster, Peter E.A. Teal, Christian Borgemeister, Baldwyn Torto

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Background: Recent malaria vector control measures have considerably reduced indoor biting mosquito populations. However, reducing the outdoor biting populations remains a challenge because of the unavailability of appropriate lures to achieve this. This study sought to test the efficacy of plant-based synthetic odor baits in trapping outdoor populations of malaria vectors. Methodology and Principal Finding: Three plant-based lures ((E)-linalool oxide [LO], (E)-linalool oxide and (E)-β-ocimene [LO + OC], and a six-component blend comprising ( E)-linalool oxide, (E)-β-ocimene, hexanal, β-pinene, limonene, and ( E)-β-farnesene [Blend C]), were tested alongside an animal/human-based synthetic lure (comprising heptanal, octanal, nonanal, and decanal [Blend F]) …

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Comparison Of Food-Based Attractants For Bactrocera Invadens (Diptera: Tephritidae) And Evaluation Of Mazoferm - Spinosad Bait Spray For Field Suppression In Mango, Sunday Ekesi, Samira Mohamed, Chrysantus M. Tanga Feb 2014

Comparison Of Food-Based Attractants For Bactrocera Invadens (Diptera: Tephritidae) And Evaluation Of Mazoferm - Spinosad Bait Spray For Field Suppression In Mango, Sunday Ekesi, Samira Mohamed, Chrysantus M. Tanga

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Catches of Bactrocera invadens Drew, Tsuruta, & White (Diptera: Tephritidae) in Multi-lure traps baited with six commercial food-based attractants, Mazoferm E802, Torula yeast, GF-120, Hymlure, Biolure, and Nulure were compared in mango orchards in Kenya. In 2007, Mazoferm E802 and Torula yeast were the most effective attractants and captured 2.4-2.6 times more females and 3.4-4.0 times more males than the standard Nulure. All attractants captured more females than males (ranging from 63 to 74%). In 2008, Mazoferm E802 was the most effective bait capturing 5.6 and 9.1 times more females and males, respectively, than the standard Nulure. Among all the …

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Molecular Markers Reveal Narrow Genetic Base And Culturing-Associated Genetic Drift In Teretrius Nigrescens Lewis Populations Released For The Biological Control Of The Larger Grain Borer In Africa, B. A. Omondi, J. Van Den Berg, D. Masiga, F. Schulthess Jan 2014

Molecular Markers Reveal Narrow Genetic Base And Culturing-Associated Genetic Drift In Teretrius Nigrescens Lewis Populations Released For The Biological Control Of The Larger Grain Borer In Africa, B. A. Omondi, J. Van Den Berg, D. Masiga, F. Schulthess

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In biological control, successful establishment of a natural enemy species depends on its adaptability in the introduced range including its ability to re-establish desired ecological interactions with the pest. These are affected by genetic parameters hitherto largely unresolved in biological control. The larger grain borer (LGB), Prostephanus truncatus, an invasive species from meso-America, is the most important post-harvest pest of maize in Africa. We studied the genetic structure of Teretrius nigrescens, a predatory beetle previously released for the control of the pest in Africa, to test the hypothesis that establishment patterns were a result of ecotype-environment mismatch and to follow …

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Integrated Decision Support For Sustainable And Profitable Land Management In The Lowlands Of Central Asia, Nodir Djanibekov, Rolf Sommer Jan 2014

Integrated Decision Support For Sustainable And Profitable Land Management In The Lowlands Of Central Asia, Nodir Djanibekov, Rolf Sommer

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Land use and crop production in the Khorezm region in western Uzbekistan, exemplarily for the irrigated lowlands of Central Asia, are challenged by the excessive, non-sustainable use of irrigation water and repeated water shortages on one hand, and soil degradation by secondary salinization on the other hand. One of the research objectives of the German-Uzbek Khorezm project, funded by the German Ministry for Education and Research (BMBF) and led by Center of Development Research (ZEF) of Bonn University, was to better understand options for land use and choice of technology at the farm level in order to evaluate and propose …

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Biology Of The Coconut Bug, Pseudotheraptus Wayi, On French Beans, James Peter Egonyu, Sunday Ekesi, Jacques Kabaru, Lucy Irungu Jan 2014

Biology Of The Coconut Bug, Pseudotheraptus Wayi, On French Beans, James Peter Egonyu, Sunday Ekesi, Jacques Kabaru, Lucy Irungu

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The coconut bug, Pseudotheraptus wayi Brown (Heteroptera: Coreidae), is a major pest of a wide range of economically important crops in Eastern and Southern Africa. The suitability of French beans, Phaseolus vulgaris L. (Fabales: Fabaceae) as an alternative food for mass rearing of P. wayi was determined by elucidating its development, survival, and reproduction on French bean pods in the laboratory. Development and survival of immatures on French beans was comparable to what is reported with two hosts previously used for rearing this species, namely coconut and cashew. Adults survived thrice longer and laid almost twice more eggs on the …

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Storage Of Mung Bean (Vigna Radiata [L.] Wilczek) And Pigeonpea Grains (Cajanus Cajan [L.] Millsp) In Hermetic Triple-Layer Bags Stops Losses Caused By Callosobruchus Maculatus (F.) (Coleoptera: Bruchidae), C. M. Mutungi, H. Affognon, A. W. Njoroge, D. Baributsa, L. L. Murdock Jan 2014

Storage Of Mung Bean (Vigna Radiata [L.] Wilczek) And Pigeonpea Grains (Cajanus Cajan [L.] Millsp) In Hermetic Triple-Layer Bags Stops Losses Caused By Callosobruchus Maculatus (F.) (Coleoptera: Bruchidae), C. M. Mutungi, H. Affognon, A. W. Njoroge, D. Baributsa, L. L. Murdock

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Dry mung bean and pigeonpea grains that had sustained some insect damage but fumigated before the start of the experiment were stored in triple-layer hermetic bags (Purdue Improved Crop Storage (PICS™ bags) or woven polypropylene (PP) bags for 6 months. Some of the bags were artificially infested with cowpea bruchid Callosobruchus maculatus (F.) (PICS1, PP1) while others were not (PICS0, PP0). In an additional trial, PP bags containing the grains were treated with Actellic Super® dust before being artificially infested (PP1Ac). Moisture content, live adult C.maculatus count, grain damage, weight loss, and seed germination were determined on a monthly basis. …

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Scattered Shade Trees Improve Low-Input Smallholder Arabica Coffee Productivity In The Northern Lake Kivu Region Of Rwanda, F. Pinard, J. M. Boffa, E. Rwakagara Jan 2014

Scattered Shade Trees Improve Low-Input Smallholder Arabica Coffee Productivity In The Northern Lake Kivu Region Of Rwanda, F. Pinard, J. M. Boffa, E. Rwakagara

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In suboptimal conditions for coffee growth, the use of shade tree is usually considered beneficial to production. This study aimed to evaluate this benefit in the poorly documented East African smallholder Arabica coffee systems in optimal climatic but suboptimal management conditions. In a 4 year observational trial in 50 coffee farms, the association of shade trees and coffee generated an average 55 % cherry production increase. Neither delay in berry maturation nor buffer in alternate bearing patterns were observed, probably due to the low productivity of unfertilized coffee plants. Quality wise, the presence of shade trees did not result in …

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Triple Bag Hermetic Storage Delivers A Lethal Punch To Prostephanus Truncatus (Horn) (Coleoptera: Bostrichidae) In Stored Maize, A. W. Njoroge, H. D. Affognon, C. M. Mutungi, J. Manono, P. O. Lamuka, L. L. Murdock Jan 2014

Triple Bag Hermetic Storage Delivers A Lethal Punch To Prostephanus Truncatus (Horn) (Coleoptera: Bostrichidae) In Stored Maize, A. W. Njoroge, H. D. Affognon, C. M. Mutungi, J. Manono, P. O. Lamuka, L. L. Murdock

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Clean shelled maize was stored in woven polypropylene (PP) or triple layer polyethylene (PICS™) bags in the presence of Prostephanus truncatus Horn (PP1; PICS1) or absence of it (PP0; PICS0) at ambient conditions for six months. Moisture content, live insect population, grain damage, weight loss, and germination were analyzed on a monthly basis. Temperature and relative humidity in both PICS- and PP-bag setups were monitored, as well as the oxygen and carbon dioxide levels in the PICS bags. Overall, maize stored in PICS bags had significantly lower (P<0.05) moisture content than maize stored in PP bags. Storage in PICS bag slowed growth of P.truncatus populations and blocked infestation from the surrounding storage environment. On the contrary, PP bags permitted profuse build-up of insect population and cross-infestation. At six months, grain damage was 0.0%, 3.4%, 50.5% and 73.9%, corresponding to weight loss of 0.0%, 2.0%, 36.3%, and 47.7% in PICS0, PICS1, PP0 and PP1, respectively. Germination of maize stored in PP bags dropped from 91.1% to 37.0% and 12.7% in PP0 and PP1, respectively, whereas germination of maize stored in PICS bags dropped only marginally and reached 78.1% and 71.0% in PICS0 and PICS1, respectively, in six months. Without extreme loss of grain viability, a huge decrease in insect infestation, grain damage and weight loss is achieved by storing maize in PICS bag even under P.truncatus endemic conditions. © 2014 Elsevier Ltd.

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Evaluation Of Acaricide-Treated String Curtains For Control Of Two-Spotted Spider Mite Tetranychus Urticae Koch (Acari: Tetranychidae) On Greenhouse Roses And Impact Of The String Curtain On The Predatory Mite Phytoseiulus Persimilis Athias-Henriot (Acari: Phytoseiidae), Emilie M. Deletre, Romain Bonafos, Thibaud Martin Jan 2014

Evaluation Of Acaricide-Treated String Curtains For Control Of Two-Spotted Spider Mite Tetranychus Urticae Koch (Acari: Tetranychidae) On Greenhouse Roses And Impact Of The String Curtain On The Predatory Mite Phytoseiulus Persimilis Athias-Henriot (Acari: Phytoseiidae), Emilie M. Deletre, Romain Bonafos, Thibaud Martin

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Foliar sprays of pesticides are frequently used to control two-spotted mites on rose flowers, but these also destroy predatory mites and pose a high risk of contamination for humans and the environment. Using a novel approach to avoid spray applications on rose plants, modified acaricide-treated string curtains were adapted to control the pest. Two main aims of this study were: (i) to identify the lethal concentration of string curtains treated with propargite, dicofol, flufenoxuron, acrinathrin or tau-fluvalinate (τ-fluvalinate) on Tetranychus urticae, and (ii) to test the design (feasibility) and efficiency of the string curtains to trap the phytophagous mites on …

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Cumulative Effects And Economic Benefits Of Intercropping Maize With Food Legumes On Striga Hermonthica Infestation, Charles A.O. Midega, Daisy Salifu, Toby J. Bruce, Jimmy Pittchar, John A. Pickett, Zeyaur R. Khan Jan 2014

Cumulative Effects And Economic Benefits Of Intercropping Maize With Food Legumes On Striga Hermonthica Infestation, Charles A.O. Midega, Daisy Salifu, Toby J. Bruce, Jimmy Pittchar, John A. Pickett, Zeyaur R. Khan

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The parasitic weed Striga hermonthica, commonly known as striga, is a major biotic constraint to maize production in sub-Saharan Africa (SSA) where it causes serious food insecurity and poverty in smallholder farming communities. We previously discovered an effective control method for it involving intercropping cereals with fodder legumes in the genus Desmodium, commonly known as desmodium. The objectives of the current study were to evaluate cumulative effects of intercropping maize with the commonly grown food legumes on striga infestation, and to establish any economic benefits of the same. Treatments comprised maize plots planted in monocrop stands or intercropped with five …

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Integrated Soil Fertility Management: Aggregate Carbon And Nitrogen Stabilization In Differently Textured Tropical Soils, R. M. Gentile, B. Vanlauwe, J. Six Dec 2013

Integrated Soil Fertility Management: Aggregate Carbon And Nitrogen Stabilization In Differently Textured Tropical Soils, R. M. Gentile, B. Vanlauwe, J. Six

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Soil organic matter is important to improve and sustain soil fertility in tropical agroecosystems. The combined use of organic residue and fertilizer inputs is advocated for its positive effects on short-term nutrient supply, but the effect of the integrated use on long-term stabilization of soil organic C and N is still unclear. We conducted a 1.5-y soil incubation experiment with maize (Zea mays) residue and urea fertilizer to examine the stabilization of C and N in four Sub-Saharan African soils differing in texture (sand, sandy loam, clay loam, and clay). The inputs were enriched with 13C and 15N in a …

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Seasonal Abundance Of Western Flower Thrips And Its Natural Enemies In Different French Bean Agroecosystems In Kenya, J. O. Nyasani, R. Meyhöfer, S. Subramanian, H. M. Poehling Sep 2013

Seasonal Abundance Of Western Flower Thrips And Its Natural Enemies In Different French Bean Agroecosystems In Kenya, J. O. Nyasani, R. Meyhöfer, S. Subramanian, H. M. Poehling

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The seasonal abundance of western flower thrips (WFT) [Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)] and its natural enemies on French beans in two agro-ecological zones (AEZs) (high and mid altitude) in Kenya, was studied in three growing cycles from January to December 2009. French beans were sampled every 2 weeks for WFT and natural enemies. Results show that colonization of French beans with WFT in both farm scales studied in the two AEZs started at 2- to 3-leaf stage. There was an increase in the population density of WFT from budding stage to podding/flowering stage, and it declined at crop senescence. …

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Phosphorus Agronomic Efficiency In Maize-Based Cropping Systems: A Focus On Western Kenya, J. Kihara, S. Njoroge Aug 2013

Phosphorus Agronomic Efficiency In Maize-Based Cropping Systems: A Focus On Western Kenya, J. Kihara, S. Njoroge

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Phosphorus (P) is facing a quantity and quality supply issue and increasing its use efficiency is important for its continued use and profitability in crop production. The objective of this study was to determine how agronomic efficiency of P (PAE) in different environments and management systems in western Kenya is affected by N application, inherent soil fertility and organic resources. We used data constituting over 2700 data points from 126 farm fields of 25 different studies conducted from 1996 to 2009. Potassium (K) deficiency is negligible in western Kenya while ommission of P and N result in a 50% and …

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Pushing The Envelope? Maize Production Intensification And The Role Of Cattle Manure In Recovery Of Degraded Soils In Smallholder Farming Areas Of Zimbabwe, Leonard Rusinamhodzi, Marc Corbeels, Shamie Zingore, Justice Nyamangara, Ken E. Giller Jun 2013

Pushing The Envelope? Maize Production Intensification And The Role Of Cattle Manure In Recovery Of Degraded Soils In Smallholder Farming Areas Of Zimbabwe, Leonard Rusinamhodzi, Marc Corbeels, Shamie Zingore, Justice Nyamangara, Ken E. Giller

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Soil fertility decline is a major constraint to crop productivity on smallholder farms in Africa. The objective of this study was to evaluate the long-term (up to nine years) impacts of nutrient management strategies and their local feasibility on crop productivity, soil fertility status and rainfall infiltration on two contrasting soil types and different prior management regimes in Murehwa, Zimbabwe. The nutrient management strategies employed in the study were: a control with no fertiliser, amendments of 100kg Nha-1, 100kg N+lime, three rates of manure application (5, 15 and 25tha-1) in combination with 100kg Nha-1, and three rates of P fertiliser …

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Differences In Essential Oil Content Of Berries And Leaves Of Solanum Sarrachoides (Solanaceae) And The Effects On Oviposition Of The Tomato Spider Mite (Tetranychus Evansi), Lucy K. Murungi, Hillary Kirwa, Baldwyn Torto Apr 2013

Differences In Essential Oil Content Of Berries And Leaves Of Solanum Sarrachoides (Solanaceae) And The Effects On Oviposition Of The Tomato Spider Mite (Tetranychus Evansi), Lucy K. Murungi, Hillary Kirwa, Baldwyn Torto

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Essential oils from leaves and berries of Solanum sarrachoides were obtained by hydro-distillation, analyzed by GC-MS and tested for oviposition deterrence against Tetranychus evansi. Plant oils comprised mainly of monoterpenes and fatty acids, but differed in terms of their relative abundance. The leaf oil contained mainly camphor (34.1%), limonene (8%), decanoic acid (9.3%) and hexadecanoic acid (7.3%). The berry oil contained mainly fatty acids (>20%) including hexadecanoic acid (9.8%) and dodecanoic acid (5.9%), hydrocarbons (>10%) and (E)-β-linalool (3.1%). In oviposition deterrence assays, the leaf essential oil and individual major monoterpenes compared favorably with the two positive controls, neem …

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Effects Of Mulching, N-Fertilization And Intercropping With Desmodium Uncinatum On Striga Hermonthica Infestation In Maize, Charles A.O. Midega, Jimmy Pittchar, Daisy Salifu, John A. Pickett, Zeyaur R. Khan Feb 2013

Effects Of Mulching, N-Fertilization And Intercropping With Desmodium Uncinatum On Striga Hermonthica Infestation In Maize, Charles A.O. Midega, Jimmy Pittchar, Daisy Salifu, John A. Pickett, Zeyaur R. Khan

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The parasitic weed Striga hermonthica is a major constraint to maize production in sub-Saharan Africa and causes serious food insecurity. We discovered serendipitously an effective control method for the weed that involves intercropping cereals with the fodder legume, silverleaf desmodium, Desmodium uncinatum (Jacq.) DC., through mechanisms that involve soil shading and nitrogen fixation. In the current study we investigated long-term effects of inorganic nitrogen (N), mulching and D. uncinatum, singly and in combinations, on S. hermonthica infestation, maize plant growth and grain yields. Treatments comprised sole maize with and without 120 kg N/ha; sole maize plots covered with maize straw …

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Two Sugar Isomers Influence Host Plant Acceptance By A Cereal Caterpillar Pest, G. Juma, M. Thiongo, L. Dutaur, K. Rharrabe, F. Marion-Poll, B. Le Ru, G. Magoma, J. F. Silvain, P. A. Calatayud Feb 2013

Two Sugar Isomers Influence Host Plant Acceptance By A Cereal Caterpillar Pest, G. Juma, M. Thiongo, L. Dutaur, K. Rharrabe, F. Marion-Poll, B. Le Ru, G. Magoma, J. F. Silvain, P. A. Calatayud

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Abstract Plant sugars are often considered as primary feeding stimuli, conditioning host plant acceptance by herbivorous insects. Of the nine sugars identified from methanolic extracts of seven grass species, only turanose, a sucrose isomer, was negatively correlated with the survival and growth of the noctuid larva of cereal stemborer, Busseola fusca. Sucrose was the most abundant sugar, although it did not vary significantly in concentration among the plant species studied. Using Styrofoam™ cylinders impregnated with increasing concentrations of turanose or sucrose, the two sugars had opposing effects: turanose appeared phagodeterrent while sucrose was phagostimulatory. Electrophysiological studies indicated that B. fusca …

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Farmers' Perceptions Of Cotton Pests And Their Management In Western Kenya, Charles A.O. Midega, Isaac M. Nyang'au, Jimmy Pittchar, Michael A. Birkett, John A. Pickett, Miguel Borges, Zeyaur R. Khan Dec 2012

Farmers' Perceptions Of Cotton Pests And Their Management In Western Kenya, Charles A.O. Midega, Isaac M. Nyang'au, Jimmy Pittchar, Michael A. Birkett, John A. Pickett, Miguel Borges, Zeyaur R. Khan

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Cotton (Gossypium hirsutum L.) production in western Kenya is severely affected by insect pests, resulting in poor yields in spite of the growing demand for the commodity. One of the key constraints to establishing effective pest management approaches for smallholder farmers is the lack of adequate information about farmers' knowledge, perceptions and practices in pest management. This study was therefore conducted to (1) evaluate farmers' knowledge and perceptions of cotton pests; (2) examine farmers' current practices in managing cotton pests; (3) identify pest management challenges and intervention opportunities in order to develop efficient integrated pest management (IPM) approaches. A total …

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The Impact Of Desmodium Spp. And Cutting Regimes On The Agronomic And Economic Performance Of Desmodium-Maize Intercropping System In Western Kenya, M. Kifuko-Koech, P. Pypers, J. R. Okalebo, C. O. Othieno, Z. R. Khan, J. A. Pickett, A. K. Kipkoech, B. Vanlauwe Oct 2012

The Impact Of Desmodium Spp. And Cutting Regimes On The Agronomic And Economic Performance Of Desmodium-Maize Intercropping System In Western Kenya, M. Kifuko-Koech, P. Pypers, J. R. Okalebo, C. O. Othieno, Z. R. Khan, J. A. Pickett, A. K. Kipkoech, B. Vanlauwe

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Low soil fertility, stemborers (particularly, Chilo partellus) and Striga weeds (Striga hermonthica and Striga asiatica) are major limitations to production of maize in western Kenya. The " Push-Pull" technology ("PPT") has been described as an appropriate innovative technology capable of addressing these constraints. The technology involves intercropping maize with Desmodium and planting Napier grass (Pennisetum purpureum) around the intercrop, but in the current study a modified PPT was used and Napier grass was not included. Field trials were conducted in two locations in western Kenya during 4 subsequent seasons to test the hypothesis that maize yield, the degree of Striga …

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Genetic Structure And Mating System Of Wild Cowpea Populations In West Africa, Eric B. Kouam, Remy S. Pasquet, Pascal Campagne, Jean Baptiste Tignegre, Kevin Thoen, Remi Gaudin, Jeremy T. Ouedraogo, Abdulai B. Salifu, Geoffrey M. Muluvi, Paul Gepts Jul 2012

Genetic Structure And Mating System Of Wild Cowpea Populations In West Africa, Eric B. Kouam, Remy S. Pasquet, Pascal Campagne, Jean Baptiste Tignegre, Kevin Thoen, Remi Gaudin, Jeremy T. Ouedraogo, Abdulai B. Salifu, Geoffrey M. Muluvi, Paul Gepts

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Background: Cowpea is a highly inbred crop. It is part of a crop-weed complex, whose origin and dynamics is unknown, which is distributed across the African continent. This study examined outcrossing rates and genetic structures in 35 wild cowpea (Vigna unguiculata ssp. unguiculata var. spontanea) populations from West Africa, using 21 isozyme loci, 9 of them showing polymorphism.Results: Outcrossing rates ranged from 1% to 9.5% (mean 3.4%), which classifies the wild cowpea breeding system as primarily selfing, though rare outcrossing events were detected in each population studied. Furthermore, the analyses of both the genetic structure of populations and the relationships …

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Identification Of Root-Knot Nematode Species Occurring On Tomatoes In Kenya: Use Of Isozyme Phenotypes And Pcr-Rflp, Rael Birithia, Wanjohi Waceke, Peter Lomo, Daniel Masiga Jun 2012

Identification Of Root-Knot Nematode Species Occurring On Tomatoes In Kenya: Use Of Isozyme Phenotypes And Pcr-Rflp, Rael Birithia, Wanjohi Waceke, Peter Lomo, Daniel Masiga

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Root-knot nematodes (RKN) are serious pests of tomato production in Kenya. Accurate identification of the plant parasitic nematodes is important for their effective management. A study conducted to assess their prevalence and identify RKN occurring on tomatoes in Central Kenya showed infestation of the crop in all the three districts. Of the total sampled plants (N = 900), the RKN infestation level ranged from 28 to 62%. RKN disease severity ranged from 2.5 to 5.3 in all the locations. Meloidogyne incognita, M. javanica and M. arenaria were the only species found infesting tomatoes in these areas. Female nematodes sampled from …

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Oviposition Induced Volatile Emissions From African Smallholder Farmers' Maize Varieties, Amanuel Tamiru, Toby J.A. Bruce, Charles A.O. Midega, Christine M. Woodcock, Michael A. Birkett, John A. Pickett, Zeyaur R. Khan Mar 2012

Oviposition Induced Volatile Emissions From African Smallholder Farmers' Maize Varieties, Amanuel Tamiru, Toby J.A. Bruce, Charles A.O. Midega, Christine M. Woodcock, Michael A. Birkett, John A. Pickett, Zeyaur R. Khan

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Maize (corn), Zea mays, is a genetically diverse crop, and we have recently shown that certain open pollinated varieties (OPVs) of Latin American origin possess a trait not present in mainstream commercial varieties: they produce volatiles in response to stemborer oviposition that are attractive to stemborer parasitoids. Here, we tested whether a similar tritrophic effect occurs in the African OPVs 'Nyamula' and 'Jowi'. Herbivore induced plant volatiles (HIPVs) were collected from plants exposed to egg deposition by the stemborer Chilo partellus. In a four-arm olfactometer bioassay, the parasitic wasp Cotesia sesamiae preferred samples containing HIPVs from plants with eggs to …

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Screenhouse Transmission Of Beauveria Bassiana From Infected To Non-Infected Adults Of Banana Weevil, C. A. Omukoko, J. M. Wesonga, E. M. Kahangi, L. S. Wamocho, K. N. Maniania Oct 2011

Screenhouse Transmission Of Beauveria Bassiana From Infected To Non-Infected Adults Of Banana Weevil, C. A. Omukoko, J. M. Wesonga, E. M. Kahangi, L. S. Wamocho, K. N. Maniania

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Laboratory studies have revealed great potential of entomopathogenic fungus Beauveria bassiana for use against the banana weevil, Cosmopolites sordidus, in banana. Adult banana weevils exposed to wet conidia of Beauveria bassiana suffered high mortalities ranging from 50-70% by 40 days post exposure when a concentration of 1×109 was used in the laboratory with three isolates ICIPE 273, M313 and M207 which were selected on the basis of high virulence against C. sordidus and high sporulation. However, impractical field delivery methods and high costs associated with the application of B. bassiana against C. sordidus prevent its use and commercialisation in banana …

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Management Of Alien Invasive Insect Pest Species And Diseases Of Fruits And Vegetables: Experiences From East Africa, B. Nyambo, S. Sevgan, A. Chabi-Olaye, S. Ekesi Oct 2011

Management Of Alien Invasive Insect Pest Species And Diseases Of Fruits And Vegetables: Experiences From East Africa, B. Nyambo, S. Sevgan, A. Chabi-Olaye, S. Ekesi

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The East African region is currently struggling to cope with several alien invasive insect pest species (AIS): the diamondback moth (DBM), fruit flies, Liriomyza leafminers, thrips and spider mites to name just a few. These insect pests have wide host range, are difficult to control with synthetic pesticides, and most are of quarantine status. AIS are becoming frequent pests in horticulture production systems, threat to food security, market access and rural livelihoods. The impact of these pests is aggravated by variability in climatic conditions, few taxonomic expertise for accurate and timely identification of new species, inadequate knowledge on viable alternative …

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Horticultural Pest Management And The African Economy: Successes, Challenges And Opportunities In A Changing Global Environment, S. Ekesi, A. Chabi-Olaye, S. Subramanian, C. Borgemeister Oct 2011

Horticultural Pest Management And The African Economy: Successes, Challenges And Opportunities In A Changing Global Environment, S. Ekesi, A. Chabi-Olaye, S. Subramanian, C. Borgemeister

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In many African countries, horticulture is the fastest growing agricultural sub-sector contributing significantly to national incomes. Diverse vegetables, fruits and spices are grown for domestic and export markets. Horticultural exports in Africa has increased by more than 50% in recent years and currently contributes >20% of agricultural exports by volume and income generation. Despite the growth, production has not kept pace with increasing demand due largely to biotic constraints attributed to arthropod pests. Agricultural research aimed at reducing insect pest damage can lead to increased horticultural production and improved rural livelihoods. icipe in collaboration with National Agricultural Research and Extension …

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