Host Plant Use, Phenology, and Biological Control of the Brown Marmorated Stink Bug (Hemiptera: Pentatomidae; \u3cem\u3eHalymorpha halys\u3c/em\u3e) in Northern Utah

The invasive brown marmorated stink bug, Halyomorpha halys (Stål), has become a significant agricultural and urban nuisance pest in North America, causing millions of dollars of damage to specialty fruit and vegetable crops over the past two decades. This pest uses over 170 host plant species in North America and is difficult to control with most conventional insecticides. Following the establishment of H. halys in Utah in 2012, this dissertation explores the plant host species, seasonal development, and biological control agents found in the unique climate conditions of the Intermountain West. Chapter II documents important plant species utilized by each H. halys life stage (eggs, nymphs, and adults) in urban landscapes in Utah. Catalpa speciosa (Warder) was found to be a sentinel host for H. halys, as the vast majority of eggs, nymphs, and adults were found on this tree host. Chapter III discusses H. halys phenology, the timing of seasonal development and degree-day requirements in northern Utah. These data show that a spring photoperiod plays a critical role in initiating overwintering adult activity and that H. halys is primarily univoltine, producing a single generation, with the possibility of a partial second generation. Chapter IV documented native and exotic parasitoid wasp species found attacking H. halys eggs in Utah, and most notably documents the discovery of adventive Trissolcus japonicus (Ashmead) populations on wild egg masses in Salt Lake City in 2019. Finally, chapter V discussed the efficacy of blue and yellow sticky cards in monitoring for target parasitoid wasps of H. halys. It was found that yellow cards are more attractive to parasitoids than blue, but that blue cards captured similar target species in fewer numbers, while also capturing far less bycatch (non-target species) than yellow cards. Therefore, blue cards can be used as an alternative to classically used yellow cards to effectively monitor for target parasitoids of H. halys and save on processing time due to less bycatch. Ultimately, this research provides foundational data on the ecology of H. halys in northern Utah, allowing for more effective future monitoring, management, and research of this pest in the future