Wood from trees infected with Dutch-elm disease should be buried or burned, or debarked to prevent spread of this fatal disease to healthy trees. Dutch elm-diseased trees which are cut down can contain the beetles that transmit the disease to healthy elm trees. Treatment of cut wood with insecticides such as chlorpyrifos (Dursban) or methoxychlor to salvage as firewood is not considered effective. Insecticides applied on the cut wood can not penetrate the bark, so will not come in contact with the elm bark beetles, which tunnel beneath the bark. According to chemical company representatives, complete coverage of each piece of wood is necessary, with reapplication of insecticide every three weeks until frost. With this treatment schedule, when bark beetles emerge from the cut wood, they might come in contact with the insecticide. The insecticides do not vaporize, so covering the wood with plastic will not increase effectiveness. In addition, burning insecticide-treated wood in an indoor fireplace is not recommended. Debarking the wood is effective in ridding the wood of elm bark beetles, limiting spread of the disease and there have been no problems associated with use of debarked wood for firewood.
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Written by Sherry Lajeunesse, Extension Urban Pest Management Specialist. Sept., 1997