Complementarity between Orius predators improves control of foliar and flower pests

BACKGROUND: Multispecies natural enemy assemblages may be more successful in suppressing herbivorous pests compared to low-diversity communities, especially when natural enemies complement each other regarding the niches they exploit. Orius predatory bugs are omnivorous biological control agents used in horticulture, and are widely associated with the control of flower thrips. However, species within the Orius genus may differ significantly in biological characteristics, such as size, thermal development requirements, induction of diapause, degree of omnivory, and within-plant distribution. In this study, we explored the differences in within-plant preferences and pest-control efficacy against foliar and flower pests of the predators Orius laevigatus, O. majusculus and O. minutus. RESULTS: In oviposition experiments with Gerbera jamesonii plants, we found that O. laevigatus preferred ovipositing in the flower calyx, while eggs of the other two Orius species were mainly found in the leaves. Similarly, in a greenhouse trial where gerbera plants were infested with both the western flower thrips Frankliniella occidentalis and the greenhouse whitefly Trialeurodes vaporariorum, O. laevigatus was the most effective predator against the flower thrips, but the least effective against whiteflies. When O. laevigatus was combined with O. minutus, the best control of both pests at the same time was observed. CONCLUSION: Our results suggest that the use of Orius predators for pest control may be further exploited and that species combinations that complement each other may expand the range of pests successfully controlled by anthocorids.