Effects of Some Fumigants on Mortality of the Pine Wood Nematode, Bursaphelenchus xylophilus Infesting Wooden Packages: 7. Fumigation Schedules for Pine Wood Nematode by Mixture Gas of Methyl Isothiocyanate and Sulfuryl Fluoride

摘要

Red pine packing material infested with the pine wood nematode, Bursaphelenchus xylophilus was fumigated at different temperatures and doses of mixture gas of methyl isothiocyanate (MITC) and sulfuryl fluoride (SF) (MITC 30%, SF 30%, carbon dioxide 40%) for 24 hours with 50% loading in a 100-liter fiberglass fumigation box. The data showed that complete mortality was attained at 21 g/ m~3 of MITC and 21 g/m~3 of SF (21 g/m~3 of MITC/SF) at 10°C, 18 g/m~3 of MITC/SF at 15°C and 15 g/ m~3 of MITC/SFat 25°C, respectively. A high correlation coefficient (R: 0.996) was observed between CT product and applied dose of SF, and CT products of SF for complete mortality were at each of 482 mg.h/l at 10°C, 413 mg.h/l at 15°C and 346 mg.h/l at 25°C, respectively, while a low correlation coefficient (R: 0.676) was observed between CT product and MITC dose, because of a high sorption ratio to packing material. The data from tarpaulin sheet fumigation showed that complete mortality was attained at each of 27 g/m~3 of MITC/SF at 10°C, 27 g/m~3 of MITC/SF at 15°C and 15 g/m~3 of MITC/ SF at 25°C, respectively. Some survivors, however, were confirmed at 21 g/m~3 of MITC/SF at 15°C, because of low gas concentration by gas leakage from the sheet. Doses of MITC/SF in fumigation schedule were determined by adding safety factor (1.17-1.37) to doses calculated with the CT products of SF in the 100-liter fumigation test and the tarpaulin fumigation test. Mixture gas of MITC and SF fumigation schedule for tarpaulin sheet are at each of 33 g/m~3 of MITC/SF at 10°C, 27 g/m~3 of MITC/SF at 15°C and 21 g/m~3 of MITC/SF at 25°C for 24 hours with 50% or below loading.