To develop a empirical model for predicting the spring flight period of overwintering Ips acuminatus adult, their density were monitored in Korean pine (Pinus koraiensis) forests at Chuncheon in 2015. The monitoring data of the beetles and temperature in the forests were used to develop the empirical predictive model based on degree-day model, and it was validated using the data from Korean pine forest at Wonju in 2018. The lower threshold temperature for flight (LTF) and a thermal requirement for the onset of flight activity of the beetles in spring were estimated. As the result, the LTF was estimated as 1.3 ℃ and 269.96 DD was required for the spring flight. The median flight date estimated by the empirical model was one day earlier than the observed flight date. Therefore, the model is suitable for predicting the spring flight of overwintering I. acuminatus.

• Cha Young Lee(Division of Forest Disease sand Insect Pests, National Institute of Forest Science/Department of Environmental Science and Ecological Engineering, Graduate School, Korea University)
• Youngwoo Nam(Division of Forest Disease sand Insect Pests, National Institute of Forest Science)
• Won Il Choi(Division of Forest Ecology and Climate Change, National Institute of Forest Science)