Cylindrocladium Root Rot, Leaf Spot and Stem Canker -- Cylindrocladium spp.
Host: Azalea, heliconia, rose, and spathiphyllum
Symptoms: Yellowing of lower leaves and wilting are indications of root rot. Cylindrocladium stem cankers cause a brown, internal discoloration of the stem of azalea. The vascular browning extends to approximately 1 inch above the soil line. Angular leaf spots, bounded by leaf veins, are caused by Cylindrocladium on azalea. Defoliation may occur. Root and petiole rot are common on spathiphyllum.
Conditions Favoring Disease: The disease on azaleas occurs only in greenhouses and is favored by high humidity and temperatures of approximately 85°F.
How Pathogen Survives/Disperses: The conidia are easily carried on hands and by wind and water. Water-dispersed conidia from fallen infected leaves can also wash into the soil where they can cause root rot. Microsclerotia survive in soil for years.
Photo and write up provided by Syngenta Professional Products