Effects of Sulfluramid-Treated Bait Blocks on Field Colonies of the Formosan Subterranean Termite (Isoptera: Rhinotermitidae)

Wooden boards impregnated with sulfluramid were nailed together with boards treated with acetone to form a block for placement in selected monitoring stations of 3 colonies of the Formosan subterranean termite, Coptotermes fomwsanus Shiraki, in Hallandale, FL. Under this choice-test condition, sulfluramid-treated boards initially accepted by termites were later avoided. When sulfluramid concentration was reduced, differences in feeding between sulfluramid-treated boards and boards treated with acetone only became insignificant, indicating non preferential feeding by the same population at the reduced toxicant concentration. Feeding deterrence was detected even for the reduced toxicant boards in later months for some colonies. We hypothesized an associative learning by C. formosanus to avoid feeding on The treatments. The 12-mo baiting with sulfluramid-treated blocks reduces foraging populations of the treated colonies by 52-86%. Without additional baiting, all populations substantially recovered in later years. It is suggested that lethal time (time required to kill) of a bait toxicant must be dose independent to be delivered to the majority of the population using a feeding medium.