Natural habitat increases natural pest control in olive groves: economic implications

Natural habitat at the landscape scale can promote biological control of crop pests, but farmers often regard natural habitat as a cost or a lost economic opportunity. Evaluating the benefits of promoting natural habitats in economic terms should make different management alternatives easier to compare. However, it is important to understand the mechanisms underlying the connection between natural habitat and natural pest control. In this study, we link measurements of natural habitat and ground cover with abundances of multiple natural enemy groups and biological control of the olive pest Prays oleae to describe spatial patterns in biocontrol and the economic value associated. Natural habitat increased biocontrol and crop yields by an average of 186.36 €/ha. This could be attributable to the entire community of predatory natural enemies present in the olive regardless of natural habitat. One predator species of this community, Anthocoris nemoralis, whose abundance was influenced by natural habitat, was strongly associated with elevated biocontrol. We hypothesize that this predator species could be the link between natural habitat and the biological control. Our results suggest that olive growers could stand to gain from conserving natural habitat. Moreover, our evidence suggests that minimizing the use of chopped pruning remains may result in increased biocontrol by bolstering the abundance of A. nemoralis. More generally, our study indicates that diversifying olive orchards and surrounding landscapes may improve olive yields.