In the Mid-South region of the U.S., the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), is the most economically damaging insect pest of cotton, Gossypium hirsutum (L.). During 2022 and 2023, tarnished plant bugs accounted for more than 70,000 lost bales of cotton and caused almost $50 million of economic losses in Mississippi per annum. Scouting for tarnished plant bug in cotton prior to bloom is accomplished by direct insect counts using a sweep net and indirect sampling through evaluation of cotton square (flower bud) retention. Cotton consultants across the Mid-South use a variety of square retention monitoring methods. Research was conducted in the Mississippi Delta to evaluate six different square retention monitoring methods compared to whole plant assessment in non-ThryvOn and ThryvOn cotton. Cotton was planted as a split-plot arrangement within a randomized complete block design with insecticide program as the main-plot factor and technology as the subplot factor. Cotton technology and tarnished plant bug control did not affect method of square retention monitoring, whereas sampling interval and the growth stage of cotton did. These data suggest that assessing damage to the third node during the first 2.5 weeks of squaring best reflects whole plant damage. After this time, accessing square damage in the top three nodes or third node only from the terminal until bloom offers the best sampling efficiency while reflecting whole plant damage prior to bloom. These practices could enable scouts to make management decisions in a timely manner to reduce input costs.
