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.
Solutions
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.
