WSU Extension

Hortsense

Bean
 
Disease
Common and yellow mosaics 
Curly top (Beet curly top virus) 
Damping-off 
Fusarium root rot 
Gray mold 
Rust 
White mold (Sclerotinia rot) 
Insect
Bean aphids 
Brown marmorated stink bug 
Cutworms and armyworms 
Spider mites 
Thrips 



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Caption: Spider mites and eggs under microscope
Photo by: Unknown
  
Bean : Spider mites
(revision date: 3/10/2017)


Biology
Spider mites are tiny, eight-legged mites which may range in color from yellowish to green or red. Several species may occur on beans. They typically feed on the underside of leaves, causing a yellowish stippling or speckling of the leaf. Severe infestations can cause entire leaves to turn yellow and drop, sometimes resulting in considerable leaf loss and reduced yield. Spider mite feeding is usually accompanied by webbing on the underside of leaves and between leaves and stems. Mites 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.
Select non-chemical management options as your first choice!

Chemical Management

Apply control measures when mites first appear and repeat applications as necessary.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Azamax Botanical Insecticide, Miticide, & Nematicide [Organic]
    Active ingredient: azadirachtin  |  EPA reg no: 71908-1-81268
  • Bonide Mite X RTU
    Active ingredient: clove oil, cottonseed oil, garlic oil/powder  |  EPA reg no: 4-04001
  • RID-BUGS
    Active ingredient: clove oil, cottonseed oil, garlic oil/powder  |  EPA reg no: 998920-08001
  • 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: 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