D3431: Comparison of companion plants and alternative prey for improving biocontrol of aphids by Orius laevigatus on strawberry

The use of Orius laevigatus is considered as biocontrol agent to protect strawberry crops against the aphid Macrosiphum euphorbiae. However, the lack of suitable habitats and/or food is a constraint to the growth and/or the establishment of the predator, reducing its effectiveness as biocontrol agent against M. euphorbiae. Using additional food resources such as companion plants or alternative food sources may support predator populations and associated biocontrol services they provide. We evaluated how the efficacy of O. laevigatus against M. euphorbiae could be mediated by the presence of companion plants and alternative prey. We evaluated under greenhouse conditions the effect of Lobularia maritima (alyssum) as possible companion plant, as well as Ephestia kuehniella eggs as alternative prey, on O. laevigatus populations and biocontrol service in strawberry cropping system. Predators were placed in the presence or absence of alyssum and/or E. kuehniella eggs on strawberry plants previously infested with aphids. We showed that the presence of alyssum and/or E. kuehniella eggs enhanced O. laevigatus population growth (when compared to a control group). Furthermore, we observed a steady reduction of M. euphorbiae populations when the companion plant was present alone or when it was associated with the alternative prey. Finally, combing alyssum and alternative prey resulted in the highest yield (number of fruits per plant). We demonstrated that combining alyssum, as a companion plant, and E. kuehniella eggs, as an alternative prey, could be an effective option for establishing O. laevigatus populations and for controlling aphids in strawberry cropping systems