Alternative fumigation technologies for Bursaphelenchus xylophilus-infected woods: reducing reliance on methyl...

Pine wilt disease (PWD), caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle, poses a significant global threat to pine forests. This study investigated the nematicidal efficacy of four fumigants-methyl bromide (MB), phosphine (PH₃), sulfuryl fluoride (SF), and methyl isothiocyanate (MITC)-applied both individually and in combination (PH₃+MB, SF+MB, MITC+MB, PH₃+SF, PH₃+MITC, and MITC+SF) against PWN.

Under uniform fumigation conditions, PH₃, SF, and MITC demonstrated nematicidal effects comparable with MB. Furthermore, the combination of these fumigants with MB exhibited synergistic effects in eradicating PWN. Compared with treatments with individual fumigants, incorporating small amounts of PH₃, SF, or MITC reduced the required MB dosage by at least 60% to achieve the same mortality rate. Optimal efficiency was observed with ratios of 1:9 for PH₃:MB, 1:9 for SF:MB, and 3:7 for MITC:MB. Although the combination of PH₃ with SF showed an insignificant synergistic effect, the combination of MITC with either PH₃ or SF exhibited pronounced synergy, with the optimal synergistic ratios being 1:9 for PH₃:MITC and 5:5 for SF:MITC.

This study highlights the efficacy of PH₃, SF, and MITC as potential alternatives to MB for controlling PWN. Moreover, the strong synergistic interactions observed when combining PH₃, SF, or MITC with MB offer a promising strategy to reduce MB dependency. Furthermore, the notable synergy between MITC and PH₃ or SF further supports their utility in integrated fumigation approaches for PWN management. © 2025 Society of Chemical Industry.