Comparative Effects of an Insect Growth Regulator, S-31183, Against the Formosan Subterranean Termite and Eastern Subterranean Termite (Isoptera: Rhinotermitidae)

In a no-choice experiment, the insect growth regulator 2-[I-methyl-2(4-phenoxyphenoxy) ethoxy] pyridine (S-31183) induced presoldier formation more effectively in the eastern subterranean termite, Reticulitermes flavipes (Kollar) than in the Formosan subterranean termite, Coptotermes formosanus Shiraki. When given a choice of treated or untreated wood cubes, C. formosanus avoided feeding on cubes treated with concentrations of 1,500 and 7,500 ppm. A S-31183 concentration of 300 ppm (AI) did not deter feeding or increase presoldier formation in C. formosanus. Feeding of R. flavipes groups exposed to cubes containing 30 or 150 ppm S-31183 was not deterred, but these concentrations caused approximately 80% worker mortality by the end of the 12-wk test. The results indicate that S-31183 might control R. flavipes colonies if 30-150 ppm were applied to a bait.