Field evaluation of Thiamethoxam 2SC for management of the Western drywood termite (Isoptera: Kalotermitidae)

Abstract:
Aqueous solutions containing thiamethoxam were applied via foam and liquid to boards containing active infestations of the Western drywood termite (Incisitermes minor (Hagen)). Two sites each in northern and southern California were included in the study. Structures included in field evaluations consisted of wood-frame construction and had a long history of problems with drywood termites. All infestations were verified active and extent delimited using termite detection equipment. For the Bodega Bay and Davenport sites in northern California, a termite-feeding detector (acoustic emissions (AE)) was used while for sites in Marina Del Rey, a termite-feeding detector and portable X-ray device were used. After verifying infestations active, boards containing termites were drilled and injected with liquid or foam formulations containing thiamethoxam (0.1%, 1000 ppm). The use of detection equipment aided the identification of locations within boards containing galleries active with termites. Termite-feeding activity (measured as AE) was monitored 30 and 90 days post-treatment. After 30 days, the reduction in AE termite-feeding activity for Bodega Bay, Davenport, and Marina del Rey was 99%, 91%, and 96%, respectively. After 90 days, the reduction in AE feeding activity had increased slightly to 99%, 94%, and 98% for the same sites. Results thus far suggest subsurface injections containing thiamethoxam significantly reduces or eliminate localized infestations of drywood termites. Advantages of using advanced detection technology in conjunction with thiamethoxam are discussed.