Managing Halyomorpha halys: Effects of cold tolerance, insecticides, and linguistic uncertainty

Abstract

Managing pests effectively and efficiently requires knowledge about their biology. Likewise, clear communication about scientific research pertaining to management is needed for managers to make well-informed decisions. My research pertains to the biology of the brown marmorated stink bug, Halyomorpha halys and communication between scientists about insecticidal categorization. Halyomorpha halys is an exotic invasive species in North America. Many horticultural and agricultural plants in North America are at risk for economic damage due to the highly polyphagous nature of this species. Additionally, H. halys has become a serious nuisance pest in human-made structures in some areas when, in preparation for winter, they aggregate in sheltered structures. Therefore, factors such as cold and insecticides, which affect H. halys distribution and ability to cause crop injury are of particular interest to develop management plans. I first conducted several studies of cold tolerance on H. halys in North America. I found that H. halys exhibits a chill-intolerant cold tolerance strategy, that season, sex, and acclimation location affect cold tolerance (i.e., supercooling points), and that laboratory assays of lethal temperature were able to accurately forecast winter mortality in the field. Second, I studied H. halys diapause in more depth. I present a protocol for rearing diapausing H. halys in the laboratory that exhibit similar cold tolerance (i.e., supercooling points and lower lethal temperatures) as individuals with field-induced diapause. I found that H. halys diapause confers greater cold tolerance than a non-diapausing state, and appears to be necessary to survive overwintering. Additionally, I showed diapausing H. halys actively feed for at least three weeks post-diapause induction, but feeding is mediated by temperature and adult age. Third, I investigated and critiqued the current paradigm for determining insecticidal efficacy on H. halys. I highlighted important sublethal effects of insecticides on feeding that can significantly reduce crop injury without the necessity of high direct mortality to H. halys. Lastly, using an interdisciplinary lens I examined linguistic uncertainty as it pertains to categories and descriptors of insecticides. I demonstrated the presence and consequences of linguistically uncertain terms associated with insecticides and encouraged entomologists to more adequately acknowledge and address these uncertainties in future research.