Insecticide resistance monitoring of tarnished plant bug (Hemiptera: Miridae) populations in the Mid-Southern United States

Authors: CATCHOT, BEVERLY - Mississippi State University; GORE, JEFFREY - Mississippi State University; KRISHNAN, NATRAJ - Mississippi State University; JACKSON, RYAN - Syngenta Crop Protection; MUSSER, FRED - Mississippi State University

Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2022
Publication Date: 3/1/2022
Citation: Catchot, B., Gore, J., Krishnan, N., Jackson, R., Musser, F. 2022. Insecticide resistance monitoring of tarnished plant bug (Hemiptera: Miridae) populations in the Mid-Southern United States. Journal of Cotton Science. 26(1):31-39. https://doi.org/10.56454/HTUA7872.
DOI: https://doi.org/10.56454/HTUA7872

Interpretive Summary: The tarnished plant bug is a major pest of cotton in the Southern U. S. Control options include applications of several different chemical classes of insecticides to cotton fields when tarnished plant bugs reaching damaging populations. Due the common usage of these chemicals, resistance to several insecticide classes has been documented, so monitoring of resistance levels to insecticides currently used is needed before field control failures may occur. Several populations were tested to estimate resistance levels for commonly used insecticides during 2017 to 2019. On average, 25 to 40% of populations were determined to be resistant to thiamethoxam, imidacloprid, and/or sulfoxaflor. There were no differences among years in mean imidacloprid and thiamethoxam ; however, the mean measured levels of survival increased from 2017 to 2019 for sulfoxaflor. No differences in resistance were detected between the two primary agricultural regions of the Mid-South (Hills and Mississippi River Delta) for any of the insecticides. For each insecticide, the range between the most and least susceptible populations was greatest in the Hills region during 2018. Susceptibility to thiamethoxam was the most variable followed by imidacloprid and sulfoxaflor. It is important to continue monitoring for resistance because continued selection pressure is likely to lead to widespread reduced efficacy in the future.

Technical Abstract: Tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), is the target for multiple insecticide applications in cotton in the mid-southern U.S. Resistance to several insecticide classes has been documented, so monitoring of resistance levels to insecticides currently used is needed before field control failures occur. Several populations were tested to estimate resistance levels for commonly used insecticides during 2017 to 2019. On average, 25 to 40% of populations were determined to be resistant to thiamethoxam, imidacloprid, and/or sulfoxaflor. There were no differences among years in mean imidacloprid and thiamethoxam LC50 values; however, the mean LC50 increased from 2017 to 2019 for sulfoxaflor. No differences in resistance were detected between the two primary agricultural regions of the Mid-South (Hills and Mississippi River Delta) for any of the insecticides. For each insecticide, the range between the most and least susceptible populations was greatest in the Hills region during 2018. Susceptibility to thiamethoxam was the most variable followed by imidacloprid and sulfoxaflor. It is important to continue monitoring for resistance because continued selection pressure is likely to lead to widespread reduced efficacy in the future.