Characterization and quantification of arthropods in two maize production environments in Kenya - Nairobi (Kenya) KARI|CIMMYT : 2002 - p. 38-44 - Printed
Bt-maize offers farmers an effective and affordable option of reducing stem borer damage in maize and thus increasing food security in Kenya. However. before the deployment of Bt-maize in Kenya, there is need to examine its impacts on non- target organisms. Effects on non-target arthropods could have implications on biodiversity, natural control of the target pests and on the decomposition of organic matter in the soil. A prerequisite to the foregoing studies, is identification of the arthropods on which the non-target effects will be examined. For this reason, on-farm studies were conducted in five farms in each of two maize growing regions in the western and coastal provinces of Kenya for two seasons, to identify the major target and non-target arthropods of Bt-maize. The dominant maize cropping systems, crop varieties and agronomic practices, characteristic of each respective region, which were identified through a preliminary survey were used in the study farms. Arthropods in the maize farms were monitored weekly, using pitfall, sticky and water traps, and by destructive sampling of maize plants thrice a season. The non-target~ were preserved in 70%alcohol for later identification, whereas the targets (stem borer$) were identified and reared singly for possible parasitoid emergence. The stem borers in Western Province were Busseola fusca, Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae), Sesamia calumistis (Lepidoptera: Noctuidae) and Cryptophlebia leucotreta (Lepidoptera: Torticidae), while in the Coast, they were C. partellus, C. orichalcociliellus, S. calamistsis and Cr. leucotreta in descending order of abundance. Among the non-targets, the parasitoids of stem borers in the Coast were Cotesia flavipes Cameron, C. sesamiae (Cameron), Chelonus curvimaculutus Cameron (Hymenoptera: Braconidae), Goniozus indicus Ashmead (Hymenoptera: Bethylidae), Dentichasmias basseolue Heinrich (Hymenoptera: Ichneumonidae) and Pediobius furvus Gahan (Hymenoptera, Eulophidae), while in western, they were, C. sesumiae and D. busseolae. Some of the commonly recovered predator groups belonged to the families formicidae, araneida, coccinelidae, forficulidae and carabidae. Other potential parasitoid and predator groups recovered are also presented. The only pollinator was the honeybee, while the decomposers of organic matter, were termites and earthworms. The potential arthropods on which the non-target effects of Bt-maize may be examined are discussed.