Complementarity among Orius species enhances pest control of foliar and flower pests

Abstract: Orius predatory bugs (Hemiptera: Anthocoridae) are omnivorous biocontrol agents, utilized in protected and open-field horticulture, and widely associated with the control of flower thrips. However, species within the genus Orius may differ in many biological characteristics, such as size, thermal development requirements, induction of diapause, degree of omnivory, plant preference and within-plant habitat distribution. In earlier experiments we have shown that O. majusculus prefers foraging on lower plant parts and controls better the foliar pest Echinothrips americanus, compared to the more anthophilous and widely used O. laevigatus. In this study, we further explored the habitat preferences of O. laevigatus, O. majusculus and O. minutus. In oviposition experiments in gerbera and chrysanthemum, we found that O. laevigatus preferred ovipositing in the flowering parts of the crop, while eggs of the other two Orius species were found lower in the plant canopy. Similarly, in a greenhouse trial where gerbera plants were infested with both Frankliniella occidentalis (Thysanoptera: Thripidae) and Trialeurodes vaporariorum (Hemiptera: Aleyrodidae), O. laevigatus exerted excellent control of the flower pest, while O. majusculus and O. minutus strongly suppressed the whiteflies which resided on the leaf canopy. Furthermore, when the anthophilous O. laevigatus was combined with either O. minutus or O. majusculus, excellent pest control of both pests was recorded. These results show that the use Orius predators for pest control may be further expanded based on multiple species and novel strategies, and that in opportune combinations species may complement each other and expand the range of pests successfully controlled by anthocorids.