Key Features
- Leaf spot, canker and root rot
- Long lived spores (Microsclerotia)
- Multiple species infect many hosts
Symptoms
Cylindrocladium may cause a leaf spot, stem canker, flower spot, root rot, or quick wilt depending on the host. This genus contains many species which is how so many plants can be hosts. Lower leaves yellowing and wilting are symptomatic of root rot. When forming a stem canker, Cylindrocladium causes a brown, internal discoloration of the stem with browning extending ~ 1" above the soil line. On azalea, angular leaf spots and defoliation may occur. Above ground symptoms of root rot include stunting, foliage discoloration and/or death, and wilting. These symptoms may not occur until drought stress, even though the roots may have been rotted for weeks or months prior to failure. Vascular discoloration may extend beyond root lesions. Woody stems may also have an internal distinct red-brown discoloration.
Biology
Microsclerotia formed by Cylindrocladium forms in plant tissues can survive many years in soil or media.High humidity and high temperatures (85°F) favor fungus growth. Spores may be carried in soil, water, by the wind, or on hands. This is mostly a disease that begins in the greenhouse or nursery and is introduced to the landscape.
Management Recommendations
Remove and destroy infected plants and fallen leaves. In addition, cull healthy appearing plants around the known infected plants as they too may be infected. Be careful not to contaminate surrounding plants with contaminated soil or plant debris.
Effective Pesticides
Active Ingredients include: Thiophanate-methyl
Resources
- Not satisfied with ID? Contact the Purdue Plant and Pest Diagnostic Lab
- Sign Up for the Purdue Landscape Report
