Assessing susceptibility of selected southern highbush blueberry cultivars to chilli thrips (Scirtothrips dorsalis)

Chilli thrips (Scirtothrips dorsalis) are an invasive pest that is becoming increasingly significant in blueberry plantings in Florida. This pest inflicts damage by feeding on young foliage, leading to bronzing, curling, and darkening of leaves, which reduces yield and plant vigor. While chemical control remains the primary strategy for management, cultivar resistance presents a sustainable and complementary approach. We assessed the susceptibility of various blueberry cultivars to chilli thrips and explored how plant traits influence thrips abundance and damage across six southern highbush blueberry (SHB) cultivars under both field and greenhouse conditions. Field trials were conducted in Umatilla, Florida, using a randomized complete block design. Weekly monitoring of thrips populations and foliar damage ratings was performed over eight weeks. Among the cultivars tested, ‘Avanti,’ ‘Sentinel,’ and ‘Optimus’ were found to harbor the highest populations of thrips; however, ‘Sentinel’ and ‘Avanti’ consistently displayed the most severe foliar damage, followed by ‘Optimus.’ In contrast, ‘Arcadia,’ ‘Albus,’ and ‘Colossus’ supported similar numbers of thrips, but ‘Albus’ exhibited significantly less damage, indicating potential tolerance or resistance mechanisms. Greenhouse trials are currently ongoing, with preliminary observations showing cultivar-specific differences in damage severity under controlled infestation. We are evaluating associated plant traits such as canopy density, light interception, chlorophyll content, and leaf nitrogen to explain the variation in thrips density and plant susceptibility expressed in injury symptoms. These findings improve our understanding of cultivar-level resistance and can help inform integrated pest management (IPM) strategies and breeding programs aimed at addressing chilli thrips in SHB production systems.