Shifts in carpenter ant (Hymenoptera: Formicidae) management strategies with introduction of new management tools and application techniques

Abstract:
Carpenter ants are major structural pests in the United States, Canada, and Scandinavian countries. With the advent of non-repellent chemicals and more attractive baits, shifts have occurred in management strategies that include either perimeter sprays or baiting as the sole method for control. Four tools or techniques were investigated for efficacy in carpenter ant management. One laboratory study showed the transfer of Termidor® (fipronil) among colony members following exposure to a single ant that had died after exposure to a dry treated surface. Ants from this secondary exposure were transferred to a third colony where mortalities of 41% and 72% were observed. Laboratory colonies also were used to study transfer of fipronil (0.001%) found in Maxforce Carpenter Ant Bait Gel®. Toxic effects were transferred from the initially exposed colony through two successive transfers. After two weeks, 100% mortality occurred in the initial colony, 57% mortality after the first transfer, and 46% mortality after the second transfer. In a field study using perimeter spray applications as the sole method of management, 17 homes with infestations received a perimeter spray of Termidor® (fipronil), TalstarOne® (bifenthrin), or TempoUltra® (cyfluthrin). After treatments, ants were not observed at 100% of the fipronil treated sites, 83% of the bifenthrin treated sites, and 80% of the cyfluthrin treated sites. Another study compared applications of bifenthrin using a power sprayer and a compressed-air hand sprayer for the control of carpenter ants. Infestations were controlled with power spraying at 40% of the sites compared to control at 80% of the sites sprayed with a compressed-air hand sprayer. The latter method allowed more precise placement of a smaller amount of chemical.