Intercropping maize with legumes or cassava is one of the most common systems in Africa, including Cameroon. Yet few or no studies have addressed how lepidopteran stem borers and their natural enemies populations are affected in these agro-ecosystem. We are investigating the effects of intercropping on the incidence and severity of maize stem borers and on the impact of their natural enemies in the humid-forest zone of Cameroon with particular reference to Busseola fusca (Fuller) (Lepidoptera: Noctuidae) the most economically important borer in this agro-ecosystem of Cameroon. Field experiments were designed, comparing maize monocrops with maize/legume or maize/cassava intercrops in two spatial arrangements, within row combination, row and strip planting. Destructive and non-destructive sampling methods were used to assess the factors that might lead to a possible reduction of pest densities and an increased impact of parasitoids in the different cropping patterns. Intercropping of maize with non-host plants decreased the number of egg batches laid by B. fusca and altered the distribution of egg batches. However, the mean number of eggs per batch was not affected by intercropping systems, but higher egg parasitism in the intercrop. Busseola fusca larvae, the predominant borer species in the study area, was significantly regulated within the intercropping system. Stem borer incidence on the maize monocrop was earlier and significantly increased with time. Whereas, in the intercropping plots stem borers colonization and establishment were significantly delayed. However, the presence or absence of non-host plant within the cropping system did not seem to interfere with Eldana saccharina (Walker) (Lepidoptera: Pyralidae) colonization and establishment.
Species 1: Lepidoptera Noctuidae Busseola fusca (African maize stalk borer)
Species 2: Lepidoptera Pyralidae Eldana saccharina (African sugarcane borer)
Keywords: intercropping, stem borer
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