Effects of intercropping on maize stemborers and their natural enemies

Abstract The effects of maize–cowpea intercropping on three lepidopteran stemborers (Chilo partellus(Swinhoe)C. orichalcociliellus(Strand) andSesamia calamistisHampson) and their natural enemies were studied in Kenya. Oviposition was not affected by intercropping, but significantly fewer larvae and pupae were found in the intercrop. Egg parasitism was significantly higher in the intercrop reaching as high as 80% and was positively density dependent. Larval and pupal parasitism remained between 3 and 20%, but neither of these were affected by intercropping or host density. The main predators, ants and wandering spiders, were not augmented by intercropping, but an inverse relationship in abundance was found between these two predator groups. It is concluded that maize intercropped with cowpea has only limited potential as a method of controlling the key pests in maize.