Baythroid 2 pyrethroid insecticide is a newly introduced cotton insecticide from Mobay Chemical Corporation. Field trials have shown Baythroid 2 to be highly efficacious on foliar feeding lepidoptera and boll weevil. Comparative trials have indicated that Baythroid 2 has a higher degree of activity on boll weevil, at rates designed for Heliothi s control, than other pyrethroids at their respective use rates. Laboratory, greenhouse, and field cage studies, as well as additional field trials, have been conducted to further investigate the activity of Baythroid 2 against boll weevil. Laboratory trials have shown a high level of contact activity when the material is applied topically to boll weevils. Behavioral studies have also shown a strong antifeedant effect on boll weevils exposed to treated cotton leaves for up to 7-days after treatment.