Push-pull is a cereal cropping system that has recently been reported to reduce incidences of ear rots and mycotoxins in maize. However, the effectiveness and mechanism involved is not yet understood. This study determined, the (i) socio-economic and agronomic factors associated with the occurrence of ear rots and contamination of maize with mycotoxins in different cropping systems in western Kenya, (ii) impact of insect management under push-pull cropping system in managing aflatoxin and fumonisins, (iii) role of soil health improvement under push-pull on the population of mycotoxin-producing fungi and (iv) effect of desmodium roots exudates on mycotoxin producing fungi of maize.

Knowledge on aflatoxin was higher among elderly aged 45 to 60 years while knowledge of ear rots increased with level of education and non-push-pull respondents were more knowledgeable. Aflatoxin levels significantly increased with stemborer infestation of maize. Stemborer and fall armyworm damage, Fusarium ear rot infection, A. flavus and F. verticillioides populations were significantly (P < 0.05) reduced under push-pull cropping system. Aflatoxin levels were not significantly different between cropping systems, but fumonisin were significantly lower under push-pull cropping system. There was positive and significant correlation among insect damage, ear rot, ear rot fungi and mycotoxin levels in maize. Populations of fungi and nutrients in soils were not significantly different between the cropping systems. Desmodium extracts roots significantly reduced radial growth of toxigenic A. flavus and F. verticillioides through reduced spore germination and germ tube elongation. In conclusion, planting maize under push-pull cropping system indirectly reduced mycotoxin contamination

College Unit
Faculty of Agriculture