These small, soft-bodied, pear-shaped insects suck the juices from leaves and stems. The foliage of infested plants will show pale or yellow spots. Whole leaves may turn yellow or brown, or may be curled, puckered, or stunted. Flower buds may be seriously damaged and the blossoms distorted. Check for clusters of these common pests on the underside of leaves or clustered on new buds, tender stems and young leaves.
Spray infested plants vigorously with water once every other morning to knock these pests from your plants, making sure to get the undersides of the leaves. If the problem persists after three such treatments, use insecticidal soap, or garlic spray. Plants that are frequently damaged by aphids can also be dusted with diatomaceous earth.
Many beneficial insects feed on aphids, including green lacewings, ladybugs, aphid midges, and braconid or chalcid wasps. These are all available commercially. Prevent future infestations with a thorough cleanup of your flower beds in the fall. This can eliminate aphid eggs that may overwinter on leaf litter or twigs of trees and shrubs.