The Bursaphelenchus xylophilus, commonly known as pinewood nematode in Japan, is a quarantine pest and is most often associated with beetles of the genus Monochamus, the pine sawyers, particularly Monochamus alternatus. Long-distance dispersal of the nematode and its vectors led to widespread losses in pine forests. Two fumigation trials were conducted for treatment of logs naturally infested with both M. alternatus and B. xylophilus. The logs were treated with ethanedinitrile or metam sodium at low temperature (-7-25.7°C and -3.7-23.1°C) for 3-d exposure in winter and early spring. Fumigation with ethanedinitrile at concentrations of 48, 68, 97 and 158 g/m³ resulted in 34.6–58.3, 91.5–97.2, 100, and 100% mortality for M. alternatus and 88.4, 77.9, 96.4, and 98.0% mortality for B. xylophilus, respectively. With Metam sodium fumigation at a dose rate of 1162 g/m³, 100% M. alternatus and 97.4% B. xylophilus were killed. These results suggest that 97 g/m³ of ethanedinitrile is adequate for complete control of M. alternatus in pine wood and >158 g/m³ is required for eradication of B. xylophilus at low temperature fumigation. These results suggest that 97 g/m³ of ethanedinitrile offers complete control of M. alternatus in pine wood and control of >98% B. xylophilus in winter or spring fumigation at a dosage rate of 158 g/m³. Therefore, ethanedinitrile has great potential for treatment of fresh pine wooden logs to manage the nematodes and the vector insects at low temperature.