Aerosol Barrier Sprays
Purchase a can of aerosol spray labeled for use against mosquitoes in an outdoor area. This spray is usually inexpensive and easy to use.
Take your aerosol barrier spray can to your yard about two to 24 hours before you use your outdoor space. The spray works best on hot days during daylight hours.
Apply the aerosol spray according to the rate recommended by the label, concentrating on dense shrubs, piles of debris on the ground, overgrown trees, around the home foundation and fence lines. Mosquitoes like cool, shaded and moist areas, so look for these sites and spray from ankle to shoulder height.
Residual Barrier Sprays
Obtain a residual insecticide labeled for elimination of mosquitoes in outdoor areas.
Mix the residual spray insecticide in water or oil according to the manufacturer's instructions if it is a concentrate product.
Pour the residual spray into a mist blower, pump sprayer, power backpack or hand sprayer.
Apply the residual spray during hot days to areas where mosquitoes rest. These are cool, shaded and damp sites, such as shed baseboards, overgrown grass under a tree, under a deck or around an air conditioner. The residual spray usually remains effective for about two weeks.
Get an insecticide make specifically for mosquito fogging. It should contain chlorpyrifos, malathion or naled as the active ingredient.
Mix the insecticide with oil, such as kerosene, fuel and diesel, according to the manufacturer's instructions.
Pour the insecticide mixture into the fogger and calibrate the machine to spray 40 gallons per hour at 5 mph to cover an area of 30 feet. If the manufacturer specifies a certain calibration setting, follow the manufacturer's instructions instead.
Apply the insecticide to the yard according to the manufacturer's instructions. You should do this in late evening, at night or early morning when the air is calm and there are many mosquitoes in the air. Fogging only kills mosquitoes on contact and does not affect any mosquitoes that come into the yard after the insecticide settles.