Sublethal effects of selected insecticides on Halyomorpha halys (Hemiptera: Pentatomidae) feeding

The brown marmorated stink bug, Halyomorpha halys (Stål), is a highly polyphagous invasive pest that can cause economic damage to many high-value crops such as apples, peaches, soybeans, and corn. As integrated pest management (IPM) programs are developed, insecticides, whether organic certified or conventional, will play a critical role in management of this pest. Looking beyond the lethal effects, insecticides at sublethal doses can still influence feeding behaviors and consequently economic injury. Quantifying these sublethal effects is especially important for H. halys management because not only is it common for the bug to experience sublethal doses due to highly mobile adults but, in addition, for many chemicals the lethal dose is well above the labeled rate. Sublethal effects can render a pest functionally dead after exposure if the pest no longer feeds. Anti-feedant effects should be considered when creating an IPM plan to allow for a more accurate picture of how an insecticide can minimize subsequent economic damage. The objective of this study was to evaluate sublethal feeding effects of six insecticides on H. halys adults. Feeding on dry soybeans, as indicated by stylet sheath presence, was recorded for each adult after exposure to residue of a registered organic (Azadirachtin & Pyrethrins, Spinosad, or Pyrethrins) or conventional (Bifenthrin, Spinosad, or Sulfoxaflor) insecticide. Feeding frequency in the insecticide treatments was significantly different compared with the untreated check,indicating that even sublethal rates of some insecticides may provide economic benefit.