Intraguild interactions between Orius laevigatus and novel aphidophagous predators in sweet pepper

Abstract: Pest control of aphids in sweet pepper remains challenging, as effective insecticides
have been restricted under the current European policy. We selected and evaluated two novel
aphidophagous predators that may complement existing biological control agents against
aphids in preventive strategies: the micrococcinelid Scymnus interruptus (Coleoptera:
Coccinellidae) and the brown lacewing Micromus variegatus (Neuroptera: Hemerobiidae). In this study, we investigated whether these novel aphidophagous predators may suffer from
intraguild predation (IGP) by the generalist predatory bug Orius laevigatus (Hemiptera:
Anthocoridae), which is released in the sweet pepper crop for the control of thrips. In laboratory experiments, O. laevigatus preyed upon eggs of both M. variegatus and S. interruptus when no other food source was provided. The intensity of IGP however, was lower when green peach aphids Myzus persicae (Hemiptera: Aphididae) were added in the arena as extraguild prey. Furthermore, when western flower thrips Frankliniella occidentalis (Thysanoptera: Thripidae) were added in the arenas, no IGP was observed. In a greenhouse experiment where sweet pepper crops were infested with both aphids and thrips, we found that the addition of O. laevigatus did not have a negative effect on the control of aphids exerted by either M. variegatus or S. interruptus, and it even improved aphid control in combination with the latter. Based on these results, we conclude that both novel aphidophagous predators may be combined with O. laevigatus in the presence of extraguild prey.