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.
Root rot causing foliage dieback on gerbera daisies
Fungal root decay on Lisianthus roots