Evaluating the host-plant preference of tobacco thrips ( Frankliniella fusca Hinds (Thysanoptera: Thripidae)) on peanut, thryvOn, and non-thryvOn cotton

Tobacco thrips, Frankliniella fusca Hinds (Thysanoptera: Thripidae), are economically important early-season pests of seedling cotton and peanut in the southern United States, causing stand loss, delayed growth, and transmission of tomato spotted wilt virus (TSWV) in peanut. Historically, managing F. fusca has depended on insecticide seed treatments and in-furrow applications. However, control efforts are becoming more limited due to insecticide resistance and the partial suppression of virus transmission. ThryvOn cotton, which expresses the Bt protein Cry51Aa2.834_16, suppresses thrips feeding and reproduction without causing high mortality, raising questions about how this trait may influence thrips host use in mixed cropping systems. We evaluated oviposition preference and population abundance of F. fusca on peanut, ThryvOn cotton, and non-ThryvOn cotton using greenhouse no-choice, two-choice, and three-choice assays, as well as a field experiment in which all crops were planted side by side. Across all greenhouse assays, F. fusca consistently laid the greatest number of eggs on peanut, intermediate numbers on non-ThryvOn cotton, and the fewest on ThryvOn cotton. Field results closely reflected these patterns, with peanut supporting significantly higher egg, nymph, and adult densities throughout early vegetative growth, while ThryvOn cotton consistently harbored the lowest thrips populations. Our findings suggest that F. fusca exhibits a preference for peanut over cotton, particularly ThryvOn cotton, indicating that reduced host suitability of ThryvOn cotton may influence early-season thrips distribution in diversified cropping systems. Although thrips movement was not measured, this preference highlights the need to consider interactions when developing regional management strategies.