A baseline survey was conducted to determine the occurrence and distribution of soil nematodesassociated with cotton in major growing areas in Kenya. Such baseline data on soil nematodeabundance, diversity and ecosystem function in cotton ecosystems are valuable in providing a basis forcomparison with organisms from transgenic cotton fields. Transgenic cotton plants expressing Cry1Ac and Cry2Ab proteins, from the soil bacterium Bacillus thuringiensis (Bt), provide effective control oflepidopteran pests. However, the potential effects of these proteins on soil nematofauna are unknown inKenya. Soil samples were collected from nine locations of western (Odiado, Angorom and Ochundolocations), coast (Baharini, Mpeketoni and Witu locations) and central (Kajiji, Tebere and Nyangatilocations) Province. Nematodes were extracted and recovered from soil samples using the White head and Hemming tray method and identified under a light microscope according to their morphologicalcharacters. They were classified according to their feeding habits. Twenty seven genera of plantparasites, bacteriovores, fungivores, predators and omnivores were identified. Bacterial, fungal feedingand parasitic nematodes were the most abundant trophic groups across all Provinces. There weresignificant differences in the numbers of bacteriovores (P ≤ 0.01) and plant parasites (P ≤ 0.05) betweenthe provinces but no difference was observed in the numbers of fungal feeding nematodes. There was asignificant difference in genus richness within locations in western and coast provinces (P < 0.001). Thecombined maturity index (_MI) did not vary significantly within the locations. The Shannon index (H')showed variations within locations in western (P < 0.001) and coast Province (P ≤ 0.01). Soil texture, Pand K were correlated with abundance of some nematode genera. The bacteria feeders, Acrobeles andRhabditis showed positive correlations to K (r = 0.592, P < 0.05 and r = 0.128, P ≤ 0.05) and P (r = 0.406, P≤ 0.05, and r = 0.252, P < 0.05) while Aphelenchus was positively correlated to P (r = 0.375, P ≤ 0.05). Theplant parasitic genera Meloidogyne and Pratylenchus showed significant negative correlation to N (r = -0.513, P ≤ 0.05 and r = -0.226, P ≤ 0.05). It is clear from this baseline data that plant parasitic and freeliving nematodes are widespread in cotton fields and any potential effects of Bt cotton on thesenematodes may affect the nematode community structure and their ecosystem functions.© 2010 Academic Journals.
