Efficacy of methyl bromide and alternative fumigants against pinewood nematode in pine wood samples

Abstract

Alternatives to methyl bromide fumigation are needed for the phytosanitary treatment of log exports. Among the potential alternative, fumigants are phosphine, and sulfuryl fluoride, which are already in use for other commodities and are labeled for use on wood products. Ethanedinitrile is being used for log treatment in Australia and its registration for that purpose is being sought in other countries. These alternative fumigants were tested against the pinewood nematode, in a range of artificially infested wood samples with high moisture content and, in some cases, the bark layer intact on the surface exposed to the fumigant. Phosphine and sulfuryl fluoride successfully eliminated pinewood nematodes on pine wood chips but neither was completely effective on pine blocks with intact bark. Ethanedinitrile was effective on pine chips, blocks and logs at all the doses tested: 40–100 mgL−1 for 24 h at 20 °C. Ethanedinitrile appears to be a promising alternative to methyl bromide for the fumigation of pine logs. Further testing at lower temperatures and doses, and with commercial-scale log loads, is recommended.