Field and Laboratory Evaluations of Chlorantraniliprole as a Termiticide in Southern Arizona

The desert subterranean termite, Heterotermes aureus (Snyder), is the predominant termite of economic importance in the arid southwest. Chlorantraniliprole, a relatively new nonrepellent, slow acting termiticide has been shown to be capable of being transferred among colony members through social interactions, and thus may be effective beyond its original site of application. Using field grids, we evaluated the colony-level effects of chlorantraniliprole on H. aureus foraging activity. Repeated laboratory soil bioassays at 3, 15, 27 and 39 mo postapplication were performed to determine the effects of chlorantraniliprole on termite mortality and tunneling activity. Additionally, field tests of chlorantraniliprole were completed on 10 structures infested with H. aureus. In the experimental grids, the zone surrounded by a chlorantraniliprole perimeter was the only section in which a significant decrease in the number of termites collected occurred, but this was observed in both treatment and controls plots. Overall, no significant colony-level effects of chlorantraniliprole application were observed within the grids. Laboratory bioassays resulted in high mortality and significantly lower tunneling activity of exposed termites at all time points. In structures, the initial application of chlorantraniliprole was sufficient to control infestations in 6 out of 10 cases without supplemental applications. Additional treatments were confined to areas that had not been treated previously. Results show that chlorantraniliprole is capable of achieving control of desert subterranean termites under most conditions. This is likely a result of its high toxicity instead of colony-level effects resulting from termiticide transfer.