WSU Extension

Hortsense

Kinnikinnick
 
Disease
Leaf gall 
Leaf spot 
Rust 
Insect
Aphid (Manzanita leafgall aphid) 



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Caption: Kinnikinnick leafgall aphid
Photo by: R.S. Byther
  
Kinnikinnick : Aphid (Manzanita leafgall aphid)
(revision date: 2/14/2019)


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


Non-Chemical Management
  • 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.
Select non-chemical management options as your first choice!

Chemical Management

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

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 reg no: 7401-10-34911
  • Hi-Yield Dormant Spray
    Active ingredient: oil/pet distillate  |  EPA reg no: 7401-428
  • Ortho Max Malathion Insect Spray Conc
    Active ingredient: malathion  |  EPA reg no: 239-739
  • 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 laurate  |  EPA reg no: 42697-60
  • This list may not include all products registered for this use.
Images

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Caption: Kinnikinnick leafgall aphid
Photo by: R.S. Byther
Caption: Kinnikinnick leafgall aphid
Photo by: R.S. Byther