Depending on the host plant and species of Cylindrocladium involved, damping-off, wilt, root rot, stem canker, crown rot or leaf spot may occur.
Outer root tissues die and root vascular tissue is discolored. Discoloration of vascular tissue may extend 2.5 cm (1 in) above soil line but seldom more. Root rot results in wilting even in plants several years old. Leaves turn brown and black and then fall. Cuttings may rot at base but roots develop above the rot. These plants often die after potting.
Stem and crown cankers form.
Damping-off of seedlings. Root and stem cankers develop.
Very small chlorotic leaf spots become purplish-black in color and have a light green halo. Leaves fall even if only one or a very few spots form. Twig dieback occurs if defoliation is severe.
Ferns (Polystichum, Dryopteris, Nephrolepis)
Reddish-brown leaf spots form at the base of petioles. Brown to black leaf spots have yellow halos.
Older foliage wilts and yellows. Roots die allowing the plant to be easily removed from the soil. Sunken black spots form at the base of petioles. Brown to black leaf spots have yellow halos.
caused diseases are favored by humid, warm, 23-27°C (75-80°F), conditions and overhead irrigation. Over-fertilization and other plant stresses may contribute to the problem.
- Plant Cylindrocladium-free seedlings
- Pot in sterile mix
- Propagate from only healthy stock plants since the disease spreads rapidly in most propagation beds
- Rogue out and destroy infected plants
- Rake and destroy fallen leaves
- Apply a fungicide to protect healthy plants (Contact Penn State Extension to obtain a list of fungicides currently recommended for use.
- Avoid overhead watering
Home or Commercial Planting
- Remove and destroy severely affected plants
Indepth, scientific treatment of this organism
- Crous, P. W. 2002. Taxonomy and pathology of Cylindrocladium (Calonectria) genera. 294 pp. 320 b & w illustrations. APS Press. 1-800-328-7560) $69.00.