A mosquito control evaluation was conducted in the Ohio river basin using a Cessna 336 Skymaster airplane converted for ULV aerial spraying. Insecticides tested included propoxur, fenthion, and synergized pyrethrins on field plots located both in Henderson Co., KY and Vanderburgh Co., IN. Mosquito populations were evaluated before and after treatments by 2 man landing counts and the use of CDC-light traps. In the Indiana plots mosquitoes were not sufficient in numbers to warrant assessing the effectiveness of treatments utilizing either landing counts or light traps. In Kentucky, however there was visible mosquito activity. Fenthion at 0.1 kg/ha, propoxur at 0.05 and 0.1 kg/ha and synergized pyrethrins at 0.004 kg/ha all provided high reduction of Aedes sollicitans as indicated by landing counts and light trap catches. High reductions also occurred in Ae. vexans numbers as indicated by light trap catches.