First Report of <i>Halyomorpha halys</i> (Hemiptera: Pentatomidae) in Montana, USA

Abstract Here, we document the first record for Montana of Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), a major agricultural and nuisance pest in many parts world. The insect was found overwintering private residence January 2021 Billings (Yellowstone Co.). A preliminary survey sites from May to October confirmed presence H. within radius at least 11 km detection. Putatively adult bugs across city summer suggest may have been present area prior 2021. Surveys conducted various regions state between 2013 2020 reported no detections halys. Yellowstone Co. previously surveyed 2017, indicating species likely arrived 2018 or before densities too low be detected. summary absence records provide herein is valuable future monitoring management efforts this economically important species.