Final Report 2009 Field Evaluations of Localized Treatments for Control of Drywood Termite Infestations in California Structural Pest Control Board, Structural Pest

2 EXECUTIVE SUMMARY Six insecticides were tested for their effectiveness against natural field infestations of Incisitermes minor (Hagen) found in homes and commercial structures from fourteen cities. A joint University and pest control industry team inspected dozens of homes and structures as possible candidates for the study. Those chosen, presented a diverse assortment of garages, attics, decks, infestations behind drywall, and crawlspace locations; all presenting a robust set of conditions to demonstrate product performance. Boards were determined as infested by drywood termites using a portable acoustic emission (AE) device that detects termite feeding. The active ingredients included in the field tests were disodium octaborate tetrahydrate (DOT, two products), d-limonene, fipronil, imidacloprid, and thiamethoxam. In addition, two untreated checks were included: treatment with water only and no treatment. In total there were eight treatments, replicated at least four times, and all were randomly assigned. Label instructions were followed and a State licensed structural pest control company conducted all applications. All boards receiving chemical treatments were drilled and treated. This process included drilling a diamond pattern of four holes spaced 3 " to 5 " inches apart, down the entire length of the board for board dimensional sizes of 2 by 8 or less. For board dimensional sizes 4 by 4 and larger and if accessible, the opposite side was drilled in similar fashion and treated. 3 Four of the above insecticides were injected as liquid; only imidacloprid and thiamethoxam was applied as pressurized foam. Pre-and post-treatment AE counts per minute were compared for all treatments. At the end of three months, although most product treatments had reduced termite-feeding activity, the reduction was not significantly different from untreated checks. The limitations when using local treatments, improvements needed in active ingredient (AI) and detection equipment, highly variable field conditions, and challenges in scientifically documenting product field performance are discussed and presented. 4 INTRODUCTION Localized treatments to control infestations of the western drywood termite, Incisitermes minor, have had a long history of use in California. The earliest published reports mention the use of arsenic dusts and chlorinated hydrocarbons (Randall and Doody 1934, Hennessy 1993). Over the last seven decades, at least 52 different chemical AIs have been tested for localized control of drywood termites (including species of Incisitermes and Cryptotermes) Most of these AIs have been phased out or banned. Currently, there are 10 AIs available for use in California and they include Some …