Aphids
Aphids on a rose bud
Aphids are one of the most common pests in gardens and landscapes. Vegetables, field crops, ornamental flowers, trees and shrubs are common targets of aphids. They are typically wingless, light green, soft-bodied, pear-shaped insects and measure about 1/16” at maturity. They can also be black, gray, yellow and red in color.
Life Cycle:
Aphids have three stages in their life cycles: egg, nymph and adult. Aphids overwinter as eggs. Aphid populations can reach high numbers extremely fast because female aphids can reproduce both sexually and asexually. In asexual reproduction, they give birth to live young. The generations can be winged and un-winged.
Damage:
Feeding in colonies, aphids damage plants by injecting their toxic saliva into the plant when they feed on plant juices in the buds, leaves, twigs, and developing fruit. The resulting damage includes stunting and distorted leaves and fruit. Aphids can also spread plant viruses from infected to uninfected plants.
You may discover aphid populations on your plants after you notice your trees or plants “raining.” Aphids excrete a substance known as honeydew when they are unable to digest all of the sap from the plants they are feeding on.
Control and Treatment:
Luckily, aphids have a number of natural enemies. Lady beetles (ladybugs) and small wasp parasites are the most successful at keeping populations under control. If you see smaller populations of aphids on your garden plants, try to knock them off the plants with a forceful stream of water before resorting to insecticides. By knocking them off the host plant, they become more exposed to natural enemies. Insecticides that control aphids commonly affect their natural enemies as well.