Previously, boll weevils,Anthonomus grandisBoheman, were dipped in chemosterilant solutions using 100% methanol, ethanol, or acetone. It was suspected that pure solvents may often have adverse effects. Boll weevils at 5 or 6 days old, dipped in 75 to 100% methanol, ethanol, or acetone, had significantly reduced flight activity. Boll weevils dipped in 25% suspensions of methanol, ethanol, or acetone containing 0.025% diflubenzuron and then irradiated had acceptable flight activity, mortality, and sperm transfer, but the females were not adequately sterilized. Male weevils dipped in 50% methanol or ethanol suspensions containing 0.05% diflubenzuron + 10 krads of irradiation had normal flight for 4 days, were adequately sterilized and transferred sperm to more females 7 days after treatment than males dipped in acetone.