Exploring the potential of phytoseiids species and the minute pirate bug, Orius laevigatus, to control Thrips parvispinus in sweet pepper

Abstract: Biological control (BC) in Spanish sweet pepper cultivation has traditionally relied
on the release of Orius laevigatus and Amblyseius swirskii to manage thrips and whiteflies.
However, the recent emergence of invasive thrips species, particularly Thrips parvispinus, has significantly disrupted the current strategy. This species poses a unique challenge due to its aggressive feeding behavior, rapid spread, and cryptic habits. Consequently, there is an urgent need to identify alternative BC strategies. To address this challenge, this study first evaluated the potential of five predatory mites, A. swirskii, Amblydromalus limonicus, Transeius montdorensis, Amblyseius cucumeris, and Amblyseius andersoni, under laboratory conditions. Their potential effectiveness was assessed based on their egg-laying and prey consumption on T. parvispinus larvae, compared to a standard prey, Frankliniella occidentalis. The results revealed that A. limonicus exhibited the highest oviposition and predation on both preys, followed by T. montdorensis and A. swirskii, which performed similarly. In contrast, A. cucumeris and A. andersoni demonstrated significantly lower effectiveness and were excluded from further testing. Building on these findings, semi-field and field experiments at growers’ level were conducted to evaluate thrips control through the preventive release of either A. limonicus, T. montdorensis, or A. swirskii, each combined with O. laevigatus. These trials demonstrated a significant reduction in T. parvispinus density across all treatments. Notably, treatments involving A. limonicus or T. montdorensis led to substantially less fruit damage compared to A. swirskii. These findings underscore the potential of integrating A. limonicus or T. montdorensis with O. laevigatus as an effective biological control strategy for managing T. parvispinus infestations in sweet pepper greenhouses.