Performance of selected insecticides against chilli thrips in Southern highbush blueberries and their effect on natural enemies

Chilli thrips, Scirtothrips dorsalis, is currently the most significant pest of southern highbush blueberries (SHB). This invasive pest poses a significant threat to blueberry production in Florida and other southern states, such as Georgia. If chilli thrips infestation were to become widespread, it is estimated it could result in an annual crop yield loss of $3–$6 billion in the US alone. Even a 10% loss in host crops could profoundly impact Florida's economy, potentially prompting shifts in international trade dynamics. Current management practices for chilli thrips are heavily reliant on chemical control. While chilli thrips resistance to current insecticides has not been reported in blueberry fields in the United States, the overuse of insecticides has led to the development of resistance across several classes of insecticides and negative effects on non-target organisms in other cropping systems. To investigate the effectiveness of pesticides currently being used in Florida, we conducted trials to assess the efficacy of selected insecticides against chilli thrips in SHB blueberries. Preliminary results showed that spinetoram (Delegate®), a common and widely used pesticide, exhibited low effectiveness, while tolfenpyrad (Apta®) and kaolin clay (Surround®) emerged as highly effective alternatives for both conventional and organic growers. In addition, Delegate® had the highest damage ratings, while spinosad (Entrust®) had the lowest damage ratings compared to the control. Variations in natural enemies were observed across different treatments. The findings of this study will be used to develop effective management strategies for chilli thrips that can be integrated into an IPM program.