How to Manage Pests

Pests in Gardens and Landscapes

Damping off of beans—Pythium spp. and Rhizoctonia solani

In plants infected with the Pythium or Rhizoctonia fungus seeds rot and young seedlings damp off. Symptoms include water-soaked or reddish brown lesions with the eventual collapse of the hypocotyl at or below ground. Occasionally, older plants are infected and develop water-soaked lesions that extend some distance up the stem, causing a linear band of dead cortical tissue. Girdling of the stem and eventual death may occur.


Planting at a temperature and at a date optimum for the plant and in soil that is moist but not overly wet is the first line of defense. Prepare raised planting beds so that the soil has good drainage. Plant shallow to minimize exposure of susceptible areas of the hypocotyl. Use light sprinkler irrigations to encourage germination and emergence, but do not overwater.

For more information, see the Damping-off Diseases in the Garden Pest Note.

Rotted seeds caused by Pythium
Rotted seeds caused by Pythium

Red-brown lesions of Rhizoctonia
Red-brown lesions of Rhizoctonia


Statewide IPM Program, Agriculture and Natural Resources, University of California
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