Photoperiod-Specific Within-Plant Distribution of the Green Stink Bug (Hemiptera: Pentatomidae) on Cotton

Sampling methods for detecting stink bugs are intensive, time-consuming, and yield variable results. In a 2-yr mark-release-observe experiment, over 500 adult green stink bugs, Chinavia hilaris (Say) (Hemiptera: Pentatomidae), were used to test for variation in nocturnal and diurnal insect distribution patterns on cotton. Field-collected stink bugs were marked or unmarked with nontoxic fluorescent sharpie markers, released, and monitored in cotton fields at peak bloom. Stink bugs were monitored visually during day and night, aided by a handheld blacklight for nighttime observations. Within-cotton distribution insect observations were categorized by plant section (i.e., bottom, middle, and top branches), by fruiting positions and leaf surface, and by concealed or exposed orientation on floral bracts and leaf surfaces. Green stink bugs were primarily distributed on the middle and top branches irrespective of photoperiod, and on bolls in first position from the main stem. Differences in stink bugs observed concealed or exposed on fruiting structures were detected. During daytime, stink bugs were primarily observed inside the bract of bolls, and when detected on leaves concealed on the lower surface. In contrast, stink bugs were primarily outside the bract of bolls at night, and when detected on leaves were exposed on an upper surface. These results support focus on assessing internal boll injury for evaluating stink bug injury to avoid the challenges in stink bug detection observed here, and point to additional study to refine stink bug density estimation when needed.