Hawthorn: Hawthorn aphid

• Categories: Hawthorn Hawthorn Insects Ornamental trees Ornamentals
• Last review date: 2026-05-15 08:29

Biology

Hawthorn aphids are yellow green to pinkish, soft-bodied insects typically found on the leaves in the spring.

Aphid feeding causes young leaves to curl tightly and turn purplish. Older leaves are crinkled and deformed.

Feeding aphids produce large amounts of honeydew, a sweet, sticky material that may attract ants or become covered with a dark growth of sooty mold.

Management Options

See "Using Integrated Pest Management (IPM) in the Landscape" for successful problem management techniques.

Non-chemical Management

Select non-chemical management options as your first choice!

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

Chemical Management

• Thorough coverage of the foliage is important, including lower leaf surfaces.
• Apply when aphids begin to increase in numbers.
• 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

If you choose to use a pesticide, some examples of products that are legal in Washington are listed below. Some products are labeled for just INDOOR or just OUTDOOR use, or may allow both uses. Be sure to choose a product appropriate for your situation. Always read and follow all label directions.

• Bug Buster-O [Organic]
  Active ingredient: pyrethrins
  EPA registration number: 1021-1771-54705
• Hi-Yield Dormant Spray
  Active ingredient: Paraffinc oil
  EPA registration number: 7401-428
• R-T-U Year-Round Spray Oil
  Active ingredient: mineral oil
  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 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.