WSU Extension


Root, stalk, and ear rots 
Seed rot and seedling blight (damping-off) 
Brown marmorated stink bug 
Corn aphids 
Corn earworm 
Cutworms and armyworms 
Spider mites 
Western spotted cucumber beetle 

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Caption: Spider mite damage on leaf
Photo by: A.L. Antonelli
Corn : Spider mites
(revision date: 6/3/2014)

Spider mites are tiny, eight-legged mites which may range in color from yellowish to green or red. They typically feed on the underside of leaves, causing a yellowish to bronze stippling or speckling of the leaf. Severe infestations can cause entire leaves to turn yellow. Spider mite feeding is usually accompanied by webbing on both sides of corn leaves. The mites may be visible as "moving dust" in the webbing. Mite infestations are worse in hot, dry, dusty conditions.
Management Options

Non-Chemical Management
  • Provide proper culture. Healthy plants are more tolerant of damage, while drought-stressed plants are more susceptible.
  • Predatory mites and insects such as ladybird beetles and green lacewings aid in control of mite populations. Avoid use of broad-spectrum insecticides which kill beneficials.
  • Hose mites from plants with a strong stream of water.
  • High levels of nitrogen in the foliage encourage spider mite reproduction. Switch to a slow-release or low-nitrogen fertilizer when practical.
Select non-chemical management options as your first choice!

Chemical Management

None recommended


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Caption: Spider mite damage on leaf
Photo by: A.L. Antonelli
Caption: Spider mites and eggs under microscope
Photo by: Unknown
Caption: Spider mites under microscope
Photo by: L.K. Tanigoshi