Aphids are those little oval-shaped insects—usually about 2 mm in size—that feed on the buds, leaves, and other tender new growth of plants1. They can be pink, black, green, yellow, and even red. They cluster together, usually on the bottom sides of leaves. Aphids leave behind a sugary sap that other insects, namely ants, love. To get rid of pesky aphids, follow these simple guidelines.
Natural aphid controls
- Encourage the growth and populations of small birds, lizards, parasitic wasps, ladybird beetles, syrphid flies, predatory midges, lady bugs, and lacewings. You can purchase some of these insects at a local garden center.
- Be aware that spraying with an insecticide may damage or kill the predator populations.
Man-made aphid remedies
- Cover your vegetables with floating row covers to protect them from aphid infestations.
- You can rinse aphids off your plants with a garden hose and pressure nozzle. If you have discovered the aphids when the colony is young and the plant leaves are still open, you can rinse them off with a strong water spray.
- If your aphid population is small and confined to one or two plants, you can pick the insects off the plants and destroy them.
- Clean up all plant debris at the base of herbaceous plants before the new growth arrives in spring to deny aphids ideal habitat.
- Use a dormant spray on trees and shrubbery to kill aphid eggs that would otherwise survive over winter.
- You can use insecticidal soaps to dispose of severe aphid infestations.
- A solution of dish detergent and water is most effective on aphid colonies.
- Malathion, rotenone, diazinon, acephate, and pyrethrum are all effective insecticides on aphid populations but check the label before use to determine their impact on other plants and aphid predators.
If you discover a healthy population of ants in your flowerbeds or lawn, check your plants and trees for aphid colonies. Ants will battle the natural enemies of aphids–the parasites and predators that will naturally subdue aphids–to feed on the honeydew sap that aphids leave behind.
Use due caution in applications of insecticides. Consult the manufacturer’s directions in all cases. Wear appropriate safety gear when applying the liquids or powders.
Reference1: Sunset Western Garden, Aphids, pg. 530 © Sunset 1995
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