A Laboratory Evaluation of Chemigation to Manage Stink Bugs (Hemiptera: Pentatomidae)

Application of insecticides for stink bug management through overhead irrigation, also called chemigation, could reduce application costs, soil compaction, and applicator exposure, while enabling growers to treat multiple fields simultaneously. The objective of these laboratory experiments was to compare knockdown, survival, and efficacy of insecticides when appropriately diluted for ground sprayer and chemigation applications. Treatments included water, bifenthrin [0.11 kg (AI)/ha] and dicrotophos [0.56 kg (AI)/ha] diluted for a ground sprayer (93.5 liters/ha), bifenthrin and dicrotophos diluted for chemigation (25,396 liters/ha), and bifenthrin and dicrotophos plus adjuvants diluted for ground sprayer or chemigation. Two- to 14-day-old adults of Nezara viridula (L.), Euschistus servus (Say), and Halyomorpha halys (Stål) were briefly submerged in appropriately diluted insecticides and then introduced into a disposable petri dish with or without food. Dishes were placed in a growth chamber provisioned with digital video cameras to monitor knockdown and feeding after insecticide exposure. Knockdown was visually assessed at 24 h after treatment followed by mortality and recovery from knockdown at 48 h after treatment. All stink bugs were knocked down within 1 h and never recovered when exposed at ground sprayer dilutions. However, many bugs survived chemigation dilutions. Less than half of the stink bugs were knocked down when exposed to dicrotophos (with or without adjuvants) and survival ranged from 17 to 77%, compared to 7-90% survival when exposed to bifenthrin at chemigation dilutions. These results strongly suggest that chemigation applications for stink bug management need to be closely examined.