Crabapple: Aphids

Biology

Aphids on crabapples may be green or reddish in color. They typically feed near the tip of growing shoots, sometimes deforming leaves and stunting terminal growth. Fruit may also be deformed. These soft-bodied insects are approximately 1/8″ long and often produce honeydew, a sweet sticky material. The honeydew may develop a growth of black sooty mold, which is an aesthetic problem but seldom harms the plant.

Management Options

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

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 predators including ladybird beetles, lacewings, syrphid (hover) fly larvae, and predatory 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

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

• Pesticide recommendations are for flowering (non-edible) crabapples.
• Thorough coverage of foliage is important.
• Use the following when aphid build up is noticed.
• Use oils during delayed dormant period.
• 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]
• Hi-Yield Dormant Spray
  Active ingredient: oil/pet distillate [EPA registration number: 7401-428]
• 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.

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