In tests of candidate insecticides against some cotton insects, ultra low volume (ULV-64 oz/acre or less) sprays of EPN (O-ethyl O-p -nitrophenyl phenylphosphonothioate) were more effective than conventional sprays in field tests against boll weevils, Anthonomus grandis Boheman; tobacco budworms, Heliothis virescens (F.); bollworms, H. zea (Boddie); and pink bollworms, Peetinophora gossypiella (Saunders). ULV sprays of Accothion® ( O,O -dimethyl 0-4-nitro- m -tolyl phosphorothioate) were effective against the pink bollworm but not against the tobacco budworm and bollworm, and the percentages of loss from the cotton leaf after application as a conventional spray were about the same (88-79%) 4 days after application, whether the pesticide was applied at rates of 1.12 or 17.6 kg/hectare. Isobenzan and isodrin, applied as conventional sprays, were the most toxic of the cyclodiene insecticides tested against larvae of tobacco budworm. Endrin applied as a conventional spray was toxic to bollworms but not to tobacco bud worms; when it was applied as ULV and conventional sprays, 83 and 89%, respectively, were lost from cotton foliage after 4 days. Lindane was the most toxic of 4 benzene hexachloride isomers applied as conventional sprays against larvae of the tohacco budworm. General Chemical CC-9287 (1,1a,3,3a;1.:5,:5a,:5h,6. decachlorooctahydro. 2-methyl-1,3,4-metheno-1 H -cyclobuta [cd]pentalcn-2-ol) applied as a conventional spray at a rate of 0.56 kg/ha gave 100% kill of larvae of tohacco budworms.