A degree-day model for forecasting adult phenology of Popillia japonica (Coleoptera: Scarabaeidae) in a temperate climate

Japanese beetle, Popillia japonica (Newman), was first detected in the United States New Jersey 1916. The beetle gradually spread to Midwest U.S. region, and confirmed Minnesota late 1960’s. has subsequently become a major invasive insect pest turfgrass several agricultural crops. As P. continues throughout U.S., other countries, it is important develop efficient ways monitor adult populations, where possible, forecast phenology of population dynamics. During 2019-2021, field trials were conducted degree-day model that can be used under Minnesota, summer climatic conditions in. We commercially available traps lures flight phenology, specifically trap-catch, along with weather data at four locations relate ambient temperatures phenology. concordance correlation coefficient ( CCC ), an index both precision accuracy, final model. Model development included evaluation simple sine-wave calculation methods, start dates between 1 Jan. April, range lower (0-15 °C) upper (20-37 thresholds. optimum found calculation, using biofix date Jan, thresholds 15 21.7 °C, respectively, for predicting 10% trap-catch. will aid future integrated management (IPM) regulatory strategies by providing tool prediction