Bioassays, droplet size determinations and tests of the effects of the spray droplets on automotive paint panels were conducted using malathion with the buffalo turbine sonic ULV sprayer, the Leco HD ULV aerosol fog generator, the London Aire model XW aerosol generator, the micro-gen model LS2-15 cold aerosol ULV generator, the micro mist ULV aerosol generator, and the TIFA model 100-E-ULV cold aerosol fog applicator. Technical grade malathion was applied in all bioassays at the rate of 1 gal per hr, vehicle speed of 10 mph. Each generator when operated at manufacturers recommended pressures gave excellent kill of caged adult mosquitoes, produced a similar droplet spectrum, and none of the generators produced droplets that were visible on automotive paint panels under 3X magnification or by unaided eye after the panels were polished using a commercial cleaner-wax car finish product.