Implications of Intercropping (Sweet Pepper - Tomato) for the Biological Control of Pests in Glasshouses

Abstract

The effects of intercropping on the distribution of pests were analysed in a cropping system comprising rows of sweet peppers cv. Mazurka [Capsicum] alternating with rows of tomatoes cv. 2209 in an 80 m2 greenhouse in the Netherlands. Infestation by Myzus persicae, Tetranychus urticae and Frankliniella occidentalis and their predators or parasitoids were compared between the rows. High densities of F. occidentalis occurred on Capsicum but not on tomatoes. M. persicae was also found on Capsicum in large numbers, but was only found in dying colonies on tomatoes. Tomatoes supported higher densities of T. urticae than Capsicum and the distribution and population dynamics of the predatory mite Phytoseiulus persimilis followed a similar pattern. These differences in pest population dynamics for the 2 crops were the result of differences in food plant suitability. It is suggested that, in intercropping systems, food plants which are least suitable for insect pests because of a defence mechanism for example, or the most favourable for stable predator-prey interactions with low pest levels, might protect other plant species by concentrating pests in a restricted area of the crop.