Control and Prevention

How to Get Rid of Aphids

• Try spraying cold water on the leaves, sometimes all aphids need is a cool blast to dislodge them.
• If you have an aphid invasion, dust plants with flour. It constipates the pests. 
• Use commercially available biological controls or by spraying with insecticidal soap or horticultural oil.
• You can often get rid of aphids by wiping or spraying the leaves of the plant with a mild solution of water and a few drops of dishwashing detergent such as Ivory.
• 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.
• Organic controls include soapy emulsion, horticultural oil (read the directions), and pyrethrum spray. Soapy water should be reapplied every 2-3 days for 2 weeks.
• Use homemade garlic or tomato-leaf sprays.

How to Prevent Aphids

• For fruit or shade trees, spray dormant oil to kill overwintering eggs.
• You can purchase beneficial insects, such as lady beetles, lacewings, and parasitic wasps, which will feed on aphids. These are usually ordered via mail—check the Internet for labs. They should keep the aphid populations controlled in the first place.
  • You can also plant flowering groundcovers in home orchards to attract predators.
• 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. 

Hosing down your plants is one way to control the aphid population in your garden.

Using Alcohol to Control Aphids

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.

Do you have more tips for controlling aphids? Let us know below!