Experiments were conducted at the Delta Research and Extension Center in Stoneville, MS during 2022 and 2023 to investigate the impact of irrigation and simulated late-season damage of tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), in cotton. The whole-plot factor compared a 90-centibar irrigation threshold and a non-irrigated treatment. Subplot factor A involved simulated damage by manual removal of squares during the fourth and fifth week of bloom. Three levels of damage at 0, 50, and 100% removal of squares above the uppermost first position white flower was subplot factor B. To understand agronomic impacts and compensation, plant heights, total node counts, nodes above white flower (NAWF), and nodes above cracked boll measurements were recorded beginning at the first week of bloom. Yield was also recorded from each plot. Results from 2022 and 2023 showed significant increases in NAWF from 100% fruit removal during both removal weeks compared to all other removal treatments; however, all treatments remained below five NAWF. No significant yield differences were found among any factor except irrigation. Threshold irrigated cotton had significantly greater yields than non-irrigated cotton. Results from this experiment agree with previous research suggesting insecticide termination could occur after the fourth week of bloom with minimal impacts to plant maturity and yield in both irrigated and non-irrigated situations.
