Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Evaluation of reduced-risk insecticides to control chilli thrips (Thysanoptera: Thripidae) and conserve natural enemies on ornamental plants.

Abstract

Ornamental plants provide valuable services that benefit people and the environment. Herbivorous insects, particularly invasive pests with little resistance from natural enemies or plant defenses, damage plants and reduce the beneficial services they provide. Reduced-risk insecticides are valuable tools to selectively reduce target pests and protect plants while presumably conserving natural enemies. Herein, we conducted 2 separate tests of a new reduced-risk insecticide, cyantraniliprole, and industry standards for the control of Scirtothrips dorsalis Hood (Thysanoptera: Thripidae), a damaging invasive insect pest of ornamental plants. We also evaluated each insecticide's compatibility with Orius insidiosus Say (Hemiptera: Anthocoridae), an important natural enemy of S. dorsalis. During laboratory evaluations, we found that spinosad was superior in acute toxicity to S. dorsalis and compatibility with O. insidiosus. Cyantraniliprole was consistently moderately toxic to S. dorsalis and O. insidiosus under lab conditions. In the field study, we found that all reduced-risk insecticides had no detectable effect on natural enemy abundance. Cyantraniliprole provided the best plant protection, with 70% less damage than the untreated control. Importantly, the effect of cyantraniliprole on S. dorsalis and plant protection depended on the application rate, such that the lowest rate tested did not reduce damage. This study demonstrates IPM tactics for managing an important invasive pest with a combination of chemical and biological control. As non-target effects of commonly used insecticides are becoming better understood, safer tools are needed to protect beneficial organisms, ornamental plants, and their services.