The influence of imidacloprid seed treatment on non-ThryvOn and ThryvOn cotton

Authors: FARMER, WALKER - Mississippi State University; GORE, JEFF - Mississippi State University; CATCHOT, ANGUS - Mississippi State University; CROW, WHITNEY - Mississippi State University; COOK, DON - Mississippi State University; PIERALISI, BRIAN - Mississippi State University; TOWEL, TYLER - Mississippi State University; BROWN, SEBE - University Of Tennessee; STEWART, SCOTT - University Of Tennessee; REISIG, DONIMIC - North Carolina State University; HUSETH, ANDERS - North Carolina State University

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2025
Publication Date: 1/31/2025
Citation: Farmer, W., Gore, J., Catchot, A., Crow, W., Cook, D., Pieralisi, B., Towel, T., Brown, S., Stewart, S., Reisig, D., Huseth, A. 2025. The influence of imidacloprid seed treatment on non-ThryvOn and ThryvOn cotton. Journal of Economic Entomology. 118(2):700-706. https://doi.org/10.1093/jee/toaf010.
DOI: https://doi.org/10.1093/jee/toaf010

Interpretive Summary: Thrips are a significant early-season pest of cotton in the United States, often requiring targeted management to mitigate their impact on plant health and yield potential. Nearly half of all planted cotton acres receive at least one synthetic pesticide application to control this pest, underscoring its economic and agronomic importance.A newly commercialized transgenic Bt trait, known as ThryvOn®, has been developed to provide enhanced protection against thrips. This study assessed the economic feasibility of supplementing ThryvOn with an insecticidal seed treatment to determine whether the combination would offer additional benefits for cotton growers. However, results indicated that incorporating an insecticidal seed treatment alongside the ThryvOn trait did not provide measurable economic advantages in field conditions. These findings suggest that ThryvOn alone may be sufficient for effective thrips control, potentially reducing the need for additional chemical inputs in cotton production systems.

Technical Abstract: In the southern United States, thrips are a significant early-season pest of cotton, often requiring targeted management to mitigate yield losses. In 2022, approximately 98% of cotton acres nationwide were infested with thrips, and 45% of those acres received insecticide treatments. Thrips injury that year led to over $113 million in losses, including both direct damage and control costs to the U.S. cotton industry.ThryvOn®, a newly commercialized Bacillus thuringiensis (Bt) trait, has been developed to enhance thrips control in cotton. However, there remains ongoing debate about whether an insecticidal seed treatment is necessary to further improve thrips management in ThryvOn varieties. To address this question, field studies were conducted to evaluate whether adding an imidacloprid seed treatment improved efficacy against tobacco thrips. Additionally, researchers assessed whether reduced rates of seed treatments—0%, 25%, 50%, 75%, and 100% of the labeled rate—offered any advantages for thrips control in ThryvOn cotton.To account for variations in pest pressure, a complementary greenhouse study was conducted under controlled conditions using the same treatments. Results indicated that imidacloprid provided only a limited benefit for thrips management in the greenhouse study and no measurable advantage in the field study. Given these findings, continued pest surveillance in ThryvOn cotton is recommended to guide foliar applications when warranted based on established thresholds. While this study does not provide definitive conclusions on the role of imidacloprid seed treatments in resistance management for ThryvOn cotton, the data suggest that any potential benefit is minimal.