An International Termite Field Test of Wood Treated with Insecticides in a Buffered Amine Oxide Carrier

摘要

A buffered amine oxide carrier has shown promise to deeply penetrate dry lumber with insecticides for termite control without using pressure treatment. Pine sapwood from trees attacked by mountain pine beetle (MPB) has increased permeability. In this study, short lengths of heavily blue stained, post-MPB lodgepole pine lumber (Pinus contorta) were treated with the buffered amine oxide carrier to borate levels less than the retentions recommended for protection against attack by the Formosan subterranean termite (average, 0.5% mass/mass boric acid equivalent), with and without the addition of organic insecticides. Additional samples were pressure treated with alkaline copper quaternary type D carbonate (ACQ-D) and disodium octaborate tetrahydrate (DOT). The boards were installed in field tests in Hawaii and Japan at sites with confirmed populations of Formosan subterranean termites. They were inspected after 2 and 5 years. Dip plus kiln-conditioning treatment with imidacloprid, permethrin plus imidacloprid, and permethrin provided good protection to post-MPB lodgepole pine lumber against termite attack over 5 years in Hawaii and Japan. Dip plus kiln-conditioning treatment with the buffered amine oxide alone provided no protection because of the low loading of borate used as the buffer. Samples that were DOT pressure treated to below the retention required for Formosan termites in American Wood Protection Association standards did not perform as well, possibly as a result of poor heartwood penetration as well as below-standard retentions. Addition of permethrin to DOT pressure treatment improved performance. ACQ pressure-treated samples did not perform as well, with two failures in Hawaii. This was also likely associated with poor penetration in the heartwood because this material was not incised.