Efficacy of Slow Acting Chitin Synthesis Inhibitor Baits on Coptotermes formosanus (Isoptera:Rhinotermitdae) in Linear Foraging Arenas

Chitin synthesis inhibitor (CSI)-based baiting programs have been successful in eliminating subterranean termite field colonies.  In Coptotermes formosanus Shiraki, it takes around 3 months to eliminate a colony with noviflumuron (CSI) bait. Although the slow acting CSIs allow the horizontal transfer of the toxicant before the onset of avoidance behavior, there is an incentive to reduce the duration of the treatment for economic purpose. The time needed for colony elimination depends on 1) spread of the toxicant in a colony of millions of individuals, 2) time required for the expression of a toxicant, and 3) molting event in individual workers. This study provides information on diffusion of a slow acting toxicant- noviflumuron (CSI) and its effect on the worker population over a linear foraging distance of ~30 m.Our results suggest that it would take a minimum of 13 days for the bait toxicant to spread amongst the foraging population of C. formosanus and another ~33 days to achieve control of the foraging population. Thus there is a possibility to reduce the time necessary to eliminate a field colony.