Intercropping Cabbage with Clover: Effects on Ground Beetles

Intercropping is used to reduce pests and diseases by decreasing their establishment or performance on the crop, and by enhancing antagonist activity. The effect of intercropping cabbage with white and subterranean clover on epigeic predator activity-density was studied in two successive years in the Netherlands. The presence of clover as an intercrop resulted in significantly higher predator activity-densities and diversity, especially early during the growing season. Several carabid species, in particular Pterostichus melanarius, Agonum dorsale, and Amara similata, were affected, whereas in the staphylinids, Philonthus spp. showed a strong preference for intercropped plots. The contribution of these predators and their larvae to pest suppression and the effect of scale in determining the final result of intercropping is discussed.