WSU Extension

Hortsense

Caption: Spider mite webbing
Photo by: A.L. Antonelli
  
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Azalea : Spider mites
(revision date: 3/10/2017)


Biology
Spider mites cause mild to severe stippling (little specks or dots) on leaves. Usually yellowish or bronzish, stippling can, in severe cases, cause leaves to turn brown and drop. Fine webbing is often present, especially on the underside of leaves. Mites may be found on the underside or both sides of leaves.
Management Options

Non-Chemical Management
  • Keep plant healthy to reduce pest problems and increase damage tolerance.
  • Switch to slow-release or lower-nitrogen fertilizers. High levels of nitrogen in the leaves can increase spider mite reproduction rates.
  • Spider mites may be washed from the plant with a strong stream of water or soapy water.
  • Predaceous mites and insect predators such as ladybird beetles may naturally control spider mite levels.
  • Avoid use of broad-spectrum pesticides that kill natural predators of spider mites. Spider mite population explosions can result.
Select non-chemical management options as your first choice!

Chemical Management


Apply when first noticed or when damage becomes evident. Test for sensitivity on azalea before applying insecticidal soaps. Be sure to apply to the underside of leaves.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Safer Brand Insect Killing Soap Conc II [Organic]
    Active ingredient: potassium laurate  |  EPA reg no: 42697-60
  • Safer Brand Insect Killing Soap with Seaweed Extract II [Organic]
    Active ingredient: potassium laurate  |  EPA reg no: 42697-59
  • This list may not include all products registered for this use.
Images
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Caption: Spider mite webbing
Photo by: A.L. Antonelli
Caption: Spider mites and eggs under microscope
Photo by: Unknown
Caption: Spider mite damage on leaf
Photo by: A.L. Antonelli
Caption: Spider mites under microscope
Photo by: L.K. Tanigoshi