SD46: Breaking the cycle: Insecticide rotation strategies for chilli thrips in southern highbush blueberries

The chilli thrips, Scirtothrips dorsalis Hood, is an invasive pest that poses a major threat to southern highbush blueberry production in Florida. Heavy infestations cause extensive leaf bronzing, distorted shoot growth, and yield losses about 80% under severe pressure. Frequent use of the same insecticide groups has led to declining control efficacy and increased risk of resistance, emphasizing the need for strategic rotation programs based on Insecticide Resistance Action Committee (IRAC) mode-of-action principles.

This field study evaluated seven insecticide rotation programs across Summer 2025 in a commercial blueberry orchard to determine their effectiveness in reducing thrips densities and associated foliar injury. Weekly sampling included direct thrips counts and visual damage ratings.

Analyses indicate that rotational programs incorporating Cyantraniliprole (Group 28), sulfoxaflor (Group 4C) and Tolfenpyrad (Group 21 A) provided more consistent and durable suppression compared to other treatments. These results underscore the importance of resistance-smart insecticide rotations in breaking the cycle of recurring infestations and sustaining long-term pest management efficacy. Findings from this study will inform best-practice guidelines for chilli thrips management in Florida’s expanding blueberry industry.