How to Identify and Get Rid of Aphids | Garden Pests | The Old Farmer's Almanac
USING ALCOHOL TO CONTROL APHIDS
Sun Nov 13 16:08:30 2016 - permalink -
Isopropanol (rubbing alcohol) works fine and is easy to find, but be sure it doesn’t have additives. Ethanol (grain alcohol) seems to work best. Alcohol usually comes in 70 percent strength in stores (or 95 percent strength purchased commercially). To make an insecticidal spray, mix equal parts 70 percent alcohol and water (or, if using 95 percent alcohol, mix 1 part alcohol to 1 ½ parts water).
You can also add alcohol to a soapy emulsion to make it more effective. For example, in a spray bottle combine 5 cups water, 2 cups alcohol, and 1 tablespoon liquid soap.
Caution: When applying an alcohol or soap spray, or a combination, always test a small area first, and apply in morning or evening, when the sun is not beating down. Watch the plant for a few days for any adverse reactions before applying more. Plants can be sensitive to alcohol and soap. Also, some soaps have additives that can damage plants—select the purest form.
Stir together 1 quart of water, 1 tsp of liquid dish soap and a pinch of cayenne pepper. Do not dilute before spraying on plants.
Companion planting can be very helpful to keep aphids away from your plants in the first place. For example:
Aphids are repelled by catnip.
Aphids are especially attracted to mustard and nasturtium. You can plant these near more valuable plants as traps for the aphids.
Nasturtiums spoil the taste of fruit tree sap for aphids and will help keep aphids off broccoli.
Garlic and chives repel aphids when planted near lettuce, peas, or rose bushes.