Kinnikinnick: Aphid (Manzanita leafgall aphid)

Biology

The manzanita leafgall aphid feeds on the leaves of kinnikinnick and other manzanita species (Arctostaphylos spp.). The aphids are grayish or greenish in color and prefer new growth. Aphid feeding causes the leaves to thicken and form bright red galls. Older galls turn brown. Severe infestations may slow the growth of the plant. Non-gall-forming aphids may also be seen occasionally on kinnikinnick. They are greenish, soft-bodied insects that may feed on leaves or stems. Honeydew, a sweet, sticky material, may be associated with aphid feeding. It may attract ants or become covered with a growth of dark sooty mold. Severe infestations may result in leaf and twig dieback.

Management Options

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

Non-chemical Management

Select non-chemical management options as your first choice!

• Syrphid fly larvae are important predators of the leafgall aphids, and will feed on them inside the galls. Avoid use of broad-spectrum insecticides which kill these and other beneficial insects such as ladybird beetles and parasitic wasps.
• Pick and destroy galls to improve appearance of aesthetically important plants.
• Avoid frequent shearing and overfertilization, which encourages succulent new growth favored by aphids.
• The non-gall-forming aphids may be washed off plants with a strong stream of water. This method is ineffective on leafgall aphids.

Chemical Management

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

• Apply when new growth begins to expand.
• Apply oils during delayed dormant period.

Approved Pesticides

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

• Hi-Yield 55% Malathion Spray
  Active ingredient: malathion [EPA registration number: 7401-10-34911]
• Hi-Yield Dormant Spray
  Active ingredient: oil/pet distillate [EPA registration number: 7401-428]
• Ortho Max Malathion Insect Spray Concentrate
  Active ingredient: malathion [EPA registration number: 239-739]
• 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.

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