Balancing pest control and conservation: Impacts of insecticides on thrips and minute pirate bugs

Integrated Pest Management (IPM) programs rely on the judicious use of insecticides that control pests while conserving natural enemies. In this study, we evaluated the field-level impact of six commonly used insecticides (Cyantraniliprole, Spirotetramat, Spinetoram, Isocycloseram, λ-cyhalothrin, and Imidacloprid) and an untreated control on thrips, the predatory bug Orius insidiosus (Say), and yield in pepper systems. Weekly monitoring of replicated field plots was conducted to evaluate changes in thrips and Orius abundance following insecticide applications. In parallel, laboratory bioassays were used to assess how residues from each insecticide affected Orius predation capacity after 24, 48 and 72-hour exposure to treated surfaces. Results showed that while some insecticides provided strong thrips suppression, they varied in their impact on Orius. Λ-cyhalothrin demonstrated effective thrips control but caused substantial reductions in both Orius abundance and predation activity. In contrast, Spinetoram, Spirotetramat, and Cyantraniliprole suppressed thrips populations effectively while maintaining Orius presence in the system. Isocycloseram and Imidacloprid also reduced thrips numbers, though with moderate non-target effects on Orius. Importantly, insecticide use had minimal influence on overall yield outcomes. These findings underscore the importance of selecting insecticides not only for their efficacy against pests but also for their compatibility with natural enemies, an essential consideration for the development of sustainable and ecologically sound IPM programs.