What to do about Aphids

What to look for & how to control them

January 13, 2011


Aphids are soft, pear-shaped, and very tiny (1/16 to 3/8 inch long). Two short tubes project backward from the tip of their abdomen. Aphids have long antennae. Some types of aphids have wings, which are transparent, longer than their body, and held like a roof over their back. Aphids may be green, pink, yellowish, black, or powdery gray. Nymphs resemble adults but are smaller and wingless.

Aphids feed on most fruit and vegetable plants, flowers, ornamentals, and shade trees. You'll find aphids throughout North America.

Their life cycle
Aphids reproduce like there's no tomorrow. Female aphids can reproduce without mating, giving birth continuously to live nymphs. Nymphs mature in 1 to 2 weeks and start producing offspring themselves.

When days become shorter in the fall, both males and females are born. They mate, and then females lay eggs on stems or in bark crevices. The eggs overwinter and hatch the following spring. In very mild climates and in greenhouses, aphids may reproduce year-round.

Both adults and nymphs suck plant sap, which usually causes distorted leaves, buds, branch tips, and flowers. Severely infested leaves and flowers may drop. As they feed, aphids excrete a sweet, sticky honeydew onto the leaves below. This allows a sooty mold to grow, which, in addition to being ugly to look at, blocks light from leaves. Also, some aphids spread viruses as they feed.

Organic damage control

  • Drench plants with strong sprays of water from a garden hose to kill aphids. (A hard, driving rainstorm will have the same effect.)
  • Keep your plants as healthy as possible, and spray dormant oil to control overwintering eggs on fruit trees.
  • Control ants that guard aphid colonies in trees from predators by placing sticky bands around the trunks.
  • Spray aphids with insecticidal soap, summer oil (on tolerant plants), and homemade garlic sprays.