Bistrifluron, a benzoylphenylurea compound, was evaluated with regard to its efficacy against workers of Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) by using three laboratory tests. In the no-choice feeding test, the mortality of bistrifluron-treated worker termites was significantly higher than that of termites exposed to the same concentrations of hexaflumuron (e.g., 6 wk at 500 ppm, 4 wk at 5,000 ppm, and 2 wk at 50,000 ppm) and untreated controls. Bistrifluron showed higher dose dependence and a faster speed of action than hexaflumuron. Both bistrifluron and hexaflumuron had feeding-deterrent effects at 5,000 ppm in the two-choice feeding test, although the mortality of worker termites exposed to bistrifluron or hexaflumuron at 5,000 ppm was not significantly different from untreated controls. In the allogrooming inhibition test, to examine effects of bistrifluron on allogrooming behavior of termites, termite movement was affected at 1 wk before termites died when exposed to 5,000 ppm bistrifluron. These results indicate bistrifluron is effective as a bait toxicant at 5,000 ppm; however, bistrifluron may cause some feeding repellency at > or = 5,000 ppm.