WSU Extension


Spider mites 

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Caption: Citrus red mite damage on skimmia
Photo by: R.S. Byther
Skimmia : Spider mites
(revision date: 2/14/2019)

Spider mites vary in color from green to reddish to brown. They are extremely small and may be barely visible to the naked eye. Mites are commonly found on the underside of leaves and may be accompanied by strands of very fine webbing. Mite feeding on skimmia causes leaves to appear stippled or speckled with very small, yellowish dots. Heavy feeding may result in leaves appearing bronzed, sometimes with very little green tissue remaining. Spider mites are often worse in hot, dry, dusty conditions.
Management Options

Non-Chemical Management
  • Natural enemies such as ladybird beetles, lacewings, and predaceous mites help control spider mite populations. Avoid use of broad-spectrum insecticides which kill these beneficials. Insecticide use may result in spider mite population explosions.
  • Wash spider mites from plants with a strong stream of water.
  • Keep plants healthy to increase pest tolerance.
  • High levels of nitrogen in the foliage encourage spider mite reproduction. Switch to a low-nitrogen or slow-release fertilizer.
Select non-chemical management options as your first choice!

Chemical Management

Apply insecticide to underside of leaves when mobile mites are discovered. A second application may be necessary about 7 days later. If oils are used, apply during delayed dormant period (just prior to budswell).

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • All Seasons Horticultural & Dormant Spray Oil Conc [Organic]
    Active ingredient: oil/pet distillate  |  EPA reg no: 4-80
  • Hi-Yield Dormant Spray
    Active ingredient: oil/pet distillate  |  EPA reg no: 7401-428
  • 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.

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Caption: Citrus red mite damage on skimmia
Photo by: R.S. Byther