Control of some houseflies on some West Indian islands with metepa, alpholate, and trichlorfon baits

Two chemosterilants, metepa and alpholate and an insecticide, trichlorfon were applied in sweetened baits in the pits of all privies on 3 islands in the West Indies for control of houseflies, Musca domestica L. Semiweekly treatments were made, first with granular baits and then with sugar syrup. On Grand Turk, 1 percent metepa liquid bait usually induced sterility in excess of 80 percent and reduced fly abundance more than 90 percent over 18 months. On Mayaguana, 1 percent liquid apholate bait produced about 60-80 percent sterility over three months under less favourable conditions and reduced fly abundance 50-80 percent. On San Salvador, 1 percent liquid trichlorfon bait reduced fly abundance 50-90 percent. The flies did not develop resistance to the chemosterilants during two years of exposure; instead the fertility of the treated strain apparently declined slightly (AU)