Standardized field trials in cotton and bioassays to evaluate resistance of tobacco thrips (Thysanoptera: Thripidae) to insecticides in the southern United States

Authors: KROB, JESSICA - University Of Tennessee; STEWART, SCOTT - University Of Tennessee; BROWN, SEBE - University Of Tennessee; KERN, DAWSON - University Of Tennessee; GRAHAM, SCOTT - University Of Tennessee; PERKINS, CLAY - Helena Agri-Enterprise; HUSETH, ANDRES - North Carolina State University; KENNEDY, GEORGE - North Carolina State University; REISIG, DOMINIC - North Carolina State University; TAYLOR, SALLY - Virginia Tech; TOWLES, TYLER - Louisiana State University; KERNS, DAVID - Texas A&M University; THRASH, BENJAMIN - University Of Arkansas; BATEMAN, NICK - University Of Arkansas; COOK, DON - Mississippi State University; CATCHOT, ANGUS - Mississippi State University

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/6/2022
Publication Date: 9/13/2023
Citation: Krob, J., Stewart, S., Brown, S., Kern, D., Graham, S., Perkins, C., Huseth, A., Kennedy, G., Reisig, D., Taylor, S., Towles, T., Kerns, D., Thrash, B., Bateman, N., Cook, D., Catchot, A. 2023. Standardized field trials in cotton and bioassays to evaluate resistance of tobacco thrips (Thysanoptera: Thripidae) to insecticides in the southern United States. Journal of Economic Entomology. 115(5):1693–1702. https://doi.org/10.1093/jee/toac136.
DOI: https://doi.org/10.1093/jee/toac136

Interpretive Summary: Leaf-dip bioassays to evaluate if tobacco thrips in cotton production regions have evolved resistance to foliar-applied insecticides and the performance of commonly applied foliar insecticides for managing thrips. Field trials were conducted from 2018 to 2021 in Arkansas, Tennessee, Mississippi, and Texas to evaluate several insecticides including acephate, dicrotophos, dimethoate, lambda-cyhalothrin, imidacloprid, and spinetoram. Dose-response bioassays with acephate suggest that tobacco thrips have developed resistance to acephate and other organophosphate insecticides with highest levels observed in Arkansas, Tennessee, and the Delta region of Mississippi. Tobacco thrips only showing consistent signs of resistance to lambda-cyhalothrin. Resistance levels for other insecticides were highly variable.

Technical Abstract: Foliar-applied insecticide treatments may be necessary to manage thrips in cotton (Gossypium hirsutum L.) under severe infestations or when at-planting insecticide seed treatments do not provide satisfactory protection. The most common foliar-applied insecticide is acephate. Field observations in Tennessee suggest that the perfor¬mance of acephate has declined. Thus, the first objective was to perform leaf-dip bioassays to assess if tobacco thrips, Frankliniella fusca (Hinds) (Thysanoptera: Thripidae), in cotton production regions have evolved resist¬ance to foliar-applied insecticides. A second objective was to assess the performance of commonly applied foliar insecticides for managing thrips in standardized field trials in Arkansas, Tennessee, Mississippi, and Texas. For both objectives, several insecticides were evaluated including acephate, dicrotophos, dimethoate, lambda-cyhalothrin, imidacloprid, and spinetoram. Field trials and bioassays were completed from 2018 to 2021. Dose-response bioassays with acephate were performed on tobacco thrips field populations and a susceptible laboratory popula¬tion. Bioassay results suggest that tobacco thrips have developed resistance to acephate and other organophos¬phate insecticides; however, this resistance seems to be most severe in Arkansas, Tennessee, and the Delta region of Mississippi. Resistance to other classes of insecticides were perhaps even more evident in these bioassays. The performance of these insecticides in field trials was variable, with tobacco thrips only showing consistent signs of resistance to lambda-cyhalothrin. However, it is evident that many populations of tobacco thrips are resistant to multiple classes of insecticides. Further research is needed to determine heritability and resistance mechanism(s).