Cylindrocladium Root Rot

Cylindrocladium spp.

Key Features


  • Leaf spot, canker and root rot
  • Long lived spores (Microsclerotia)
  • Multiple species infect many hosts
Cylindrocladium on juniper
Cylindrocladium in conifer nursery
Early symptoms of root rot include foliar issues like discoloration and leaf death.

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

Lookalikes


landscape report
Purdue Landscape Report
PPDL
Plant & Pest Diagnostic Laboratory