Preliminary trials of the ethanedinitrile fumigation of logs for eradication of Bursaphelenchus xylophilus and its vector insect Monochamus alternatus

BACKGROUND The nematode Bursaphelenchus xylophilus and its insect vectors from the Monochamus genus are major global quarantine pests of timber products. Owing to the phase‐out of methyl bromide for plant quarantine and preshipment treatments, an alternative fumigant is essential. Based on preliminary laboratory studies on the efficacy of ethanedinitrile ( C 2 N 2 ) to B. xylophilus and Monochamus alternatus , three quarantine trials were conducted at three dosages and three temperatures. Potential for inhalation exposure was assessed by monitoring atmospheric C 2 N 2 in relation to the threshold limit value. RESULTS Concentration × time products ( Ct ) of 398.6, 547.2 and 595.9 g h m −3 were obtained for each trial. A 100% mortality of B. xylophilus and M. alternatus larvae at 23 ± 4 °C and 10 ± 4 °C occurred with a load factor of pine logs of 46% and at 3 ± 1 °C with a load factor of 30%. During all fumigations, atmospheric levels of C 2 N 2 20 m downwind were below the TLV . During aeration, levels 10 and 5 m downwind were below the TLV after 0.4 and 1 h respectively. CONCLUSION For the purpose of quarantine or phytosanitary treatment, specific doses of C 2 N 2 at the trial temperatures could control B. xylophilus and M. alternatus larvae without significant inhalation risk to workers.