The Status of Green Gram Production, Pest and Disease Manage - ment in Parts of Lake Victoria Basin
Machocho, Alex K.
Rugumamu, C. P.
Birgen, J. K.
MetadataShow full item record
Diseases, pests, inappropriate agronomic practices and drought are the most important constraints to grain legumes production in Sub-Saharan Africa. Crop failures are frequent in the climatically marginal areas, making occasional reliance on relief food supplies a reality in affected populations. There is a need to develop and promote drought tolerant crops such as the green gram, Vigna radiate (L) Wilczek, that yield reasonably with little rainfall and are resistant to pests and diseases. A baseline field survey was carried out among smallholder farmers in Homa Bay and Busia Districts in Kenya and Magu District in Tanzania to establish the extent of green gram production in the Lake Victoria Basin. The survey was intended to investigate green gram land races, common pests and diseases, as well as methods of pest and disease control. It emerged that green gram is a traditional food crop in the study areas and there are established land races/varieties of the crop. Pests and diseases varied in the study areas. The insects identified belonged to several families, namely Calliphoridae, Coccinellidae, Scydmaenidae, Chalcididae, Formicidae and Aphididae. Other species identified were Chrotogonus hemipterus,Catantops melanostictus and Taeniothrips sjostedti. In Magu, bean flies, thrips, aphids, pod-sucking bugs and beetles were common while in Homa Bay and Busia the major pests were cutworms, white ants, bean flies and aphids. Common green gram diseases reported were leaf curl, leaf spot, powdery mildew, blight, rust and pod rot. Bruchids and Sitophilus spp. were the most common storage pests while general wood ash, crushed fresh marigold stem and leaves were used to control field pests and diseases as sisal ash was used to control stored grain pests. Thirteen (13) land races were identified based on size, color and shape of the seeds. The land races planted in separate pilot plots to determine their performance with respect to yield, resistance to pest and diseases, and other growth factors of production like low inherent soil fertility and erratic precipitation revealed variation in germination rates, vegetative growth, flowering, pod set and maturity time. Observation on grains harvested from the ten land races yielded five more land races indicating that the land races in the study areas are heterozygous. Green gram grown in all study areas exhibit varying characteristics, hence different varieties. The crop was found to be infected with virus and fungi and was prone to various diseases. The pests attacking the crop ranged from insect species to birds and mammals.