LABORATORY EVALUATION OF THE NOVEL SOIL INSECTICIDE SILAFLUOFEN AGAINST COPTOTERMES-FORMOSANUS SHIRAKI (ISOPT, RHINOTERMITIDAE)

Effects of the new insecticide silafluofen (HOE 084498) on tunneling and survival of Formosan subterranean termites, Coptotermes formosanus Shiraki, were determined in both forced-exposure and indirect-exposure laboratory bioassays. In the indirect-exposure assays, termites were given the option of tunneling through sand treated with an emulsifiable formulation of silafluofen to reach a supplemental food source. Although C formosanus tunneling was reduced in sand containing 10 ppm silafluofen, this concentration did not cause significant mortality in the forced-exposure assay. Forced exposure to 100 ppm silafluofen killed all termites within 24 h. In tunneling assays, 500 ppm silafluofen was required to prevent complete termite penetration through the 7.5 cm tunneling arena, and greater-than-or-equal-to 1000 ppm to limit tunneling distances to 1 cm or less. In topical application assays, a 5 % dust formulation of silafluofen proved extremely toxic to C. formosanus workers, and may be useful for treatment of termite galleries within wood.