Using sodium N-methyldithiocarbamate to exterminate the pine wood nematode in wood chips

In September 1984, Finland initiated an embargo against the importation of wood chips from the U.S., Canada, and Japan. This action was taken after several shipments originating in the U.S. and Canada were found to be contaminated with the pinewood nema­ tode, Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle, the causa­ tive agent of pine wilt disease. Effective Jan. 9, 1985, Finland permanently banned the importation of softwood in the form of fuel logs, rough wood, and pulpwood from North America and Japan. The pine wood nematode is endemic in North America, and native species of pine are partially resistant to pine wilt disease. Although the disease is not known to be present in Europe, Euro­ pean pines are highly susceptible to it. Preliminary studies indicate that steam heat or immersion in hot water will kill nematodes within wood chips.1 This method has the disadvantage of increas­ ing chip weight. The exploratory study reported here indicates that treating chips with sodium N-methyldithiocar­ bamate may provide a more practical means for killing the pine wood nema­ todes in them.