Lethal and sublethal effects of insecticides on Halyomorpha halys (Hemiptera: Pentatomidae) eggs, nymphs, and adults

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, soybeans, and corn. As integrated pest management (IPM) programs are developed, insecticides will play a significant role in managing this pest. However, for insecticides to be effective in an IPM program, consideration of sublethal effects and variable toxicity among life stages should be made. Halyomorpha halys adults commonly experience sublethal doses under field conditions due to their high mobility. Additionally, all life stages of this pest can be found in a crop, which makes it possible to target the most vulnerable stage. Insecticides at sublethal doses can potentially influence the efficacy of a product through negative effects on feeding, resulting in reduced economic injury. This study evaluated mortality of eggs, nymphs, and adults exposed either topically or residually to selected insecticides. Sublethal effects on adult feeding behavior were measured through quantification of stylet sheaths (i.e., feeding sites) on dry soybean seeds. While there were no ovicidal effects following topical application to eggs, mortality from residual exposure after eclosion was high. Mortality varied by exposure method and insecticide for nymphs but was high enough to prohibit further investigation into sublethal effects. Surviving adults produced significantly fewer feeding sites than the control for some insecticides, indicating that sublethal doses may provide economic benefit through feeding suppression. Consideration of H. halys life stage, as well as anti-feedant effects, will prove useful when incorporating insecticides into IPM programs.