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University of Minnesota Extension

Quick guide to insects and diseases of beans

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Quick facts

This page highlights non-chemical practices to prevent or manage common insect and disease problems of beans. 

For more detailed information follow the links in each section.

Click on an image to enlarge it.

Viral diseases

  • Plant resistant varieties.
  • Control weeds in and around the field.

Bacterial leaf diseases

  • Plant disease resistant varieties.
  • Use drip irrigation.
  • Do not work in plants when wet.
  • After harvest, bury plants.
  • Do not save seeds from infected plants.
  • Do not use plant beans in the same field for 2 years.

More information on bacterial brown spot.

White mold

  • Use drip irrigation.
  • Leave wide spaces between plants.
  • Choose varieties with an open, upright growth form.
  • Stake vining varieties.
  • Remove infected plants.
  • Do not compost infected plants.
  • At harvest, throw away any beans with soft, discolored spots.

More information on white mold.

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  • Remove weeds and plant residue.
  • Till garden before planting.
  • Place cardboard collars or aluminum foil around plant stems when planting transplants.

More information on cutworms.

Bean leaf beetles

  • Delay planting beans until mid to late June.
  • Handpick beetles on the beans and place in a pail of soapy water.

More information on bean leaf beetles.

Spider mites

  • Keep beans properly watered.
  • Use a water hose to spray a hard stream of water on infested leaves.

More information on spider mites.

Michelle Grabowski, Extension educator and Jeff Hahn, Extension entomologist

Reviewed in 2018

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