Plum, Prune (Fresh): Aphids

Biology

Several aphid species can be found on plums, including the hop aphid and the leaf curl plum aphid. The hop aphid is yellowish to dark green. The leaf curl plum aphid is dark green to reddish in early spring and fall, and pale green in the summer. Aphids typically feed in colonies on the tips of new growth and the undersides of leaves. Infested leaves and shoots are curled and distorted. Feeding aphids produce large amounts of honeydew, a sweet, sticky material which may attract ants or become covered with a dark growth of sooty mold. Honeydew and sooty mold can reduce fruit quality.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Encourage natural predators including ladybird beetles, lacewings, syrphid flies, 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 trees with a strong stream of water before leaves curl.
• 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.

Chemical Management

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

• Apply superior type oils to manage overwintering aphid eggs. Use as needed through the growing season.
• Thorough coverage of the foliage is important, including lower leaf surfaces.
• Insecticidal soaps usually require multiple applications.
• Homeowners should not make foliar applications to trees over 10 ft tall.
• Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.

Approved Pesticides

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

• All Seasons Horticultural and Dormant Spray Oil Concentrate [Organic]
  Active ingredient: mineral oil/pet distillate [EPA registration number: 4-80]
• R-T-U Year-Round Spray Oil
  Active ingredient: oil/pet distillate [EPA registration number: 6218-78]
• Safer Brand BioNEEM Multi-Purpose Insecticide and Repellent Concentrate [Organic]
  Active ingredient: azadirachtin [EPA registration number: 70051-6-42697]
• Safer Brand Garden Defense Multi-Purpose Spray Concentrate [Organic]
  Active ingredient: clarified hydrophobic extract of neem oil [EPA registration number: 70051-2-42697]
• Safer Brand Insect Killing Soap Concentrate II [Organic]
  Active ingredient: potassium salts of fatty acid [EPA registration number: 42697-60]
• This list may not include all products registered for this use.

Additional Images