Field tests of several insecticides applied as ULV sprays by ground equipment were conducted using caged adult Aedes taeniorhynchus (Wiedemann) and Culex nigripalpus Theobald. Satisfactory mortalities of both species were obtained with chlorpyrifos (Dow MFC), fenitrothion (Sumithion Concentrate); phenthoate (Cidial ULV); propoxur (Baygon I MOS); and 3% naled (Dibrom 14) in various diluents including heavy aromatic naphtha (HAN); chevron 400 solvent, and diesel oil plus 3% ortho additive. Resmethrin (20% SBP-1382 18.5MF in Klearol) gave excellent mortality of Cx. nigripalpus but poor kill of Ae. taeniorhynchus.