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Bean: Spider mites

categories: Bean Bean Insects Vegetables

revision date: 2023-04-04 12:00

Spider mites under microscope.
Spider mites under microscope
Photo by: L.K. Tanigoshi

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

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

  • 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.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

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

Approved Pesticides

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.

  • Bonide Mite X RTU
    Active ingredient: clove oil, cottonseed oil, garlic oil/powder [EPA registration number: 4-04001]
  • RID-BUGS
    Active ingredient: rosemary oil, clove oil, sesame oil [EPA registration number: 998920-08001]
  • Safer Brand BioNEEM Multi-Purpose Insecticide and Repellent Concentrate [Organic]
    Active ingredient: azadirachtin [EPA registration number: 70051-6-42697]
  • Safer Brand Insect Killing Soap Concentrate II [Organic]
    Active ingredient: potassium salts of fatty acid [EPA registration number: 42697-60]
  • This list may not include all products registered for this use.

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