The Sakhalin pine longicorn, Monochamus saltuarius Gebler (Coleoptera: Cerambycidae), is an insect vector of the pine wilt nematode (PWN), Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle, and is widely distributed in central Korea. M. saltuarius is a forest pest that seriously damages Pinus densiflora and Pinus koraiensis forests. We examined the effect of electron beam irradiation on the mating, DNA damage and ovarian development of M. saltuarius adults and sought to identify the optimal dose for sterilizing insects. Our results suggest that pine wilt disease can be effectively controlled if a large number of sterilized M. saltuarius adults are released into the field.