In 2020, severe defoliation was reported in Abies holophylla plantations located in Hwacheon-gun, Gangwon-do. This damage was attributed to an outbreak of an unidentified sawfly species from the genus Cephalcia (Hymenoptera: Pamphiliidae). The larvae of this sawfly caused significant defoliation of the leaves. This pest has been identified as Cephalcia koreana Park & Jung, sp. nov., described as a new species in 2023. To investigate the occurrence pattern and density of C. koreana, we set up emergence traps and analyzed samples from affected branches. Our results showed that the density peaks for adults, eggs, and larvae were in mid-May, late May, and early June of 2021, respectively. However, their density decreased sharply after a notably cold spring period in 2022. Here, I aim to discuss the outbreaks of insect pests and their population dynamics.

• Cha Young Lee(The Institute of Forest Science, Kangwon National University) Corresponding author
• Youngwoo Nam(Division of Forest Insect Pests and Diseases, National Institute of Forest Science)
• Jong-Kook Jung(Department of Forest Environment Protection, Kangwon National University)