Aphids are small, soft-bodied, pear-shaped insects. They may vary in color from yellow to green to dark. Aphids typically feed in colonies on the leaves, often preferring the newer growth. Infested leaves turn yellow and may wilt or show other signs of water stress. Feeding aphids often produce large amounts of honeydew, a sweet, sticky material which may attract ants or become covered with a dark growth of sooty mold. The ants may protect aphid colonies from predators.

Management Options

Non-Chemical Management

Encourage natural enemies including ladybird beetles, lacewings, syrphid (hover) fly larvae, and parasitic wasps. Avoid use of broad-spectrum insecticides which kill beneficial insects.
Hand-wipe to help control small, localized infestations.
Wash aphids from plants with a strong stream of water. This may be ineffective on the low, dense foliage of lettuce.
Control honeydew-feeding ants.
Provide proper nutrition. High levels of nitrogen in the foliage encourage aphid reproduction. Switch to a slow-release or low-nitrogen fertilizer when practical.
Wash lettuce before eating.

Select non-chemical management options as your first choice!

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides

Follow label directions. Apply when aphids first appear.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.

Safer Brand BioNEEM Multi-Purpose Insecticide & Repellent Conc [Organic]
Active ingredient: azadirachtin | EPA reg no: 70051-6-42697
Safer Brand Insect Killing Soap with Seaweed Extract II [Organic]
Active ingredient: potassium laurate | EPA reg no: 42697-59
Surround At Home Crop Protectant
Active ingredient: kaolin clay | EPA reg no: 61842-18-56872
This list may not include all products registered for this use.

Images

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Caption: Aphid colony Photo by: A.L. Antonelli
Caption: Aphid cast skins Photo by: R.S. Byther
Caption: Aphids on kale Photo by: C.A. Miles

WSU Extension

Hortsense