Malathion and naled were applied as aerial ULV, and their effect on field populations of Aedes sollicitans (Walker) was studied. The application rate for malathion 91% was 219 ml/ha (3oz./a.) and for naled (Dibrom 14) 73 ml plus 146 ml heavy aromatic naphtha/ha (1oz. plus 2 oz./a.). Fifty separate applications were made, approximately 1600 ha (4000 a) per application. The effect on field populations was variable with a decrease in reduction levels over the 3 days post treatment. Based on actual mosquito landing counts malathion provided a more extended depression of populations. However, areas receiving naled application contained greater mosquito populations prior to treatment which prevents absolute comparison between the two insecticides.