Abstract: Lepidopteran stem borers are among field insect pests responsible for the low maize production in sub-Saharan Africa. In Kenya, Chilo partellus Swinhoe (Pyralidae), Busseola fusca Fuller (Noctuidae) and Sesamia calamistis Hampson (Noctuidae) constitute the major proportion of stemborer community. Concerted efforts to reduce stemborer populations in maize fields have been emphasized without a good understanding of potential losses associated with damage by respective stemborer speci...
Abstract: The southern root knot nematode (Meloidogyne incognita) is one of the highly polyphagous species of many cultivated plants. The losses associated with RKNs in small holder vegetable farms are not quantified but may range between 30-100% in tropical and subtropics. Application of broad spectrum nematicides is the common method of control and are to be highly toxic to humans and pollute the environment, hence the need for safer alternatives for small scale crop production systems. Bi...
Abstract: Amaranth is one of the African indigenous vegetables that is gaining popularity due to its nutritional, medicinal and economic values. Its potential as a source of food security in East Africa and most parts of the world has heightened demands for the once neglected crop. In Kenya and Tanzania, the Lepidopteran defoliators are important pests of the crop which can cause up to 100% yield loss. Little information on the population dynamics of these pests make their management difficu...
Abstract: Three neem-based biopesticides, namely Achook (0.15% Azadirachtin), Neemroc (0.03% Azadirachtin + 32% neem oil) and Neem + Com (0.03% Azadirachtin + 32% com oil) and one garlic-based product, namely GC- mite (40% garlic extract), were evaluated under laboratory, greenhouse and field conditions for their efficacy against red spider mites (Tetranychus evansi Baker and Pritchard) on tomatoes (Lycopersicum esculentum L.). A synthetic acaricide, namely Omite (57% propargite) was also us...
Abstract: Cowpea is one of the 14 species of grain legumes. It rewards insects by producing nectar and it advertises to the pollinators by producing floral volatiles. The volatiles act as cues that guide insect pollinators in terms of pollen and nectar. Floral volatile quality also influences the efficiency of pollination. Genetic manipulations involving selection of varieties with high quality floral volatiles and nectar can therefore increase pollination efficiency and hence cowpea yields....
Abstract: This study was undertaken to establish the effect of temperature on the development and survival of B. fusca, S. calamistis and C. partellus and their larval parasitoids The stem borers and the larval parasitoids were reared at 200C, 250C, 280C and 300C and their development time, survival, fecundity and longevity were recorded. These parameters were subjected to analysis of variance (ANOVA) in General Linear Model (GLM). Results showed that development of stem borer larvae varied ...
Abstract: The two initial objectives of this research project were (1) to obtain a detailed chemical description of secretions from the accessory reproductive glands CARGs) of the male desert locust, . Schistocerca gregaria Forskal, and (.2 ) to identify the chemical nature of the spermatophore and seminal fluids in order to obtain a better understanding of the roles of individ~al ARG secretions in their formation. The secretions of the 16 pairs of ARGs were subjected to disc gel electrophor...
Abstract: Fish feed protein ingredients are the most expensive and often unavailable in subSaharan Africa especially in commercial aquaculture systems. The major fish feed protein ingredient in fish farming in Kenya is fishmeal (FM) that is often times expensive and adulterated leading to low productivity of fish farming. This problem has necessitated a need for exploring alternative less expensive and easily available protein sources such as black soldier fly larvae (BSFL). This study aimed...
Abstract: The ectoparasitic mite Varroa destructor is one of the parasiteglobally reported affecting honeybee healthand causing high colony losses.Of notable importance is the associationof the mite with viruses and their transmission to honeybees which causesgreatharm to bees. Kenyan beekeepers have reportedthat bee populationshave been ondecline in recent years and therefore the need for research to establish whether Varroa destructoris negativelyaffectinghoneybee survival and development....
Abstract: Root-Knot Nematodes (RKNs) are major economically important group of plant parasitic nematodes distributed worldwide. RKNs cause over $100 billion yield losses annually on major crops. The damage caused to crops is due to plant root invasion by motile second stage juveniles (J2s). The J2s induce redifferentiation of the plant root cells into specialized feeding cells essential for nematode development. The hyperplasia and hypertrophy of cells surrounding the feeding cells lead to f...
Abstract: A study was carried out to isolate and identify the chemicals from sorghum and maize that determine the oviposition and feeding responses, respectively, of the moth and larvae of Chilo partellus a serious pest of these crops. Studies were carried out on a resistant and a susceptible cul ti var of maize (MP 704 resistant; INBRED A susceptible) as well as sorghum (IS 1044 resistant; IS 18363 susceptible). The allelochemicals were extracted sequentially with petroleum ether, ethyl ace...
Abstract: Maize lethal necrosis (MLN) is a virus disease complex that was recently reported in eastern Africa. It causes huge yield losses, hence threatening food security in the region. It is caused by a co-infection of Maize chlorotic mottle virus (MCMV) and Sugarcane mosaic virus (SCMV) in maize and other cereal crops. Thrips and beetles are known vectors of MCMV while SCMV is vectored by aphids. Since MLN is new to Africa, there are no known effective management strategies against the di...
Abstract: Tomato (Solanum lycopersicon L), is one of the most common and important vegetable crops in the world with over 18,477 hectares under tomato production in Kenya. Tomato production is however, greatly threatened by bacterial wilt (BW). Bacterial wilt, caused by Ralstonia solanacearum is a serious disease in the tropics and subtropics, causing severe losses in many agricultural crops. To control its infection, several measures have been deployed but with minimum success. Alternative ...
Abstract: The melon fly, Zeugodacus cucurbitae (Coquillett), is a serious pest of cucurbits, tree fruits and related crops in most continents of the world, including Africa. To manage the pest, most farmers in sub-Saharan Africa rely on synthetic chemicals which have detrimental effects to the environment and the habitat. Excessive use of chemicals may also lead to development of pest resistance and Z. cucurbitae has reportedly shown the most increased resistance to the used insecticides. Fo...
Abstract: Tomato (Solanum lycopersicum) is one of the important vegetables grown in Kenya. It is the second leading vegetable in terms of production and nutritional value after the potato. Tomatoes are mainly grown by small scale farmers in most arable areas with the main production areas being in Kiambu County. Production of tomatoes in Kenya has been mainly under open field conditions until recently where modified high tunnels (‘greenhouse’) were introduced. Tomato production in greenh...