Bean aphids are small, pear-shaped, dark green to black insects. These soft-bodied insects often feed in clusters on the shoot tips and leaves of new growth. Severe infestations can result in curled or deformed leaves and shoot tips. Aphid feeding can produce large amounts of honeydew, a sweet, sticky material that may attract ants or become covered with a dark growth of sooty mold. The summer form of the aphids may be found on various hosts including many vegetables, flowers, and ornamentals. The aphids typically overwinter on hosts such as euonymus and viburnum.

Management Options

Non-Chemical Management

Encourage natural predators including ladybird beetles, lacewings, syrphid (hover) fly larvae, and parasitic wasps. Avoid use of broad-spectrum insecticides which kill beneficial insects.
Hand-wipe or prune to control small, localized infestations (when practical).
Wash aphids from plants with a strong stream of water.
Control honeydew-feeding ants, which may protect aphid colonies from predators.
Provide proper nutrition. High levels of nitrogen encourage aphid reproduction. Switch to a slow-release or low-nitrogen fertilizer if necessary.

Select non-chemical management options as your first choice!

Chemical Management

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

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 Conc II [Organic]
Active ingredient: potassium salts of fatty acid | EPA reg no: 42697-60
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: Bean aphid Photo by: K. Grey

WSU Extension

Hortsense