a1 Department of Population Biology, University of Copenhagen, Denmark
a2 Department of Entomology, Swedish University of Agricultural Sciences, Uppsala, Sweden
The effects of maize–cowpea intercropping on three lepidopteran stemborers (Chilo partellus (Swinhoe) C. orichalcociliellus (Strand) and Sesamia calamistis Hampson) 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.
(Accepted March 01 1996)
c1 Henrik Skovgård, The Danish Pest Infestation Laboratory, Skovbrynet 14, 2800 Lyngby, Copenhagen, Denmark.