How to Manage Pests

Pests in Gardens and Landscapes

Root, stem, and crown rots—Fusarium, Pythium, Phytophthora, and Rhizoctonia spp.

Fusarium, Pythium, Phytophthora, and Rhizoctonia species are common fungi that infect roots and crowns of plants. Virtually all flowers are susceptible to attack by one or more of these pathogens. Dull-colored foliage or wilting followed by yellowing of plants are often the first aboveground symptoms of root and crown disease. Plants may be stunted and can eventually die. Infected roots and stems often are dark, soft, decayed, break off easily, or have brownish tips. Seedlings don’t emerge. Seeds rot in soil.


Good cultural practices and sanitation are critical control measures for all root and crown rots. Avoid excess moisture in the root zone and minimize other plant stresses. Use only pathogen-free plants or bulbs. Plant in well-drained soil or use raised beds. Don’t plant too deep. Avoid overwatering. Dig out and destroy infected plants.

For more information, see the Phytophthora Root and Crown Rot or Damping-off Diseases in the Garden Pest Notes.

Fungal root decay
Fungal root decay on lisianthus roots

Root rot causing dieback on gerbera daisies
Root rot causing foliage dieback on gerbera daisies

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