The role of intercropping different cereal species in controlling lepidopteran stemborers on maize in Kenya

Abstract:  The effects of mixed cropping systems containing maize, sorghum, millet and beans on infestations of cereals by lepidopteran stemborers and on associated parasitoids, as well as on yields and land equivalent ratios (LER) were assessed during four consecutive rainy seasons at two sites in the semi-arid eastern region of Kenya. Systems containing the non-host bean were more efficient in reducing pest densities than those with millet or sorghum only. Higher parasitism in diversified systems compared to monocrops was due to density-dependent effects rather than superior suitability of such systems to parasitoids. The maize–bean system, which had the highest proportion of bean plants, had LERs >1.65 while most other systems had LERs <1. It is concluded that mixed cropping with several cereal species has little advantages in terms of yield loss abatement due to stemborers and land use efficiency. However, including the drought-tolerant crops such as sorghum and millet in the system stabilizes food security in drought-prone areas such as eastern Kenya.