Ecological and Biological Studies of Two Larval Parasitoids on Two Vectors of the Pinewood Nematode in South Korea.

Pine wilt disease, caused by the pinewood nematode, affects , Siebold and Zucc., and Parl. in South Korea. It is primarily spread by vectors such as Hope and (Gebler). However, biological control research in this context remains limited in South Korea. We identified 15 parasitoids of these vectors, namely, two ectoparasitic larval parasitoids, (Fabricius) and Chao, both in Braconidae, Hymenoptera. A field survey was conducted in Pohang from 2018 to 2020 to elucidate the ecological and biological characteristics of these parasitoids. The average parasitism rates of were 6.3% and 1.0%, whereas those of were 0.7% and 0.5% on and , respectively. Both and appeared to prefer to , but a statistically significant difference was observed only for ( < 0.001). The peak season and tree height with the highest parasitism rate of coincided with the period when larvae lived beneath the bark and the highest larval density of and occurred in pine trees. These findings provide valuable information for determining the optimal release time and height for to achieve effective biological control.