Cylindrocladium root rot

Cylindrocladium root rot is a severe fungal disease caused by species of Cylindrocladium (now classified as Calonectria). This soil-borne pathogen primarily targets the root system, causing decay that hinders the plant's ability to absorb water and nutrients, often leading to rapid plant mortality.

The host range is extensive, affecting diverse species including ornamental plants, timber trees, and tropical crops. Notable examples of vulnerable plants include the black walnut and banana, where the pathogen can cause significant economic losses in both nurseries and established plantations.

Symptomatology involves leaf yellowing (chlorosis), wilting, and subsequent necrosis of foliage. Below ground, the roots exhibit distinct dark brown to black lesions, significant tissue softening, and eventually complete disintegration of the root system, which is the defining clinical feature of this infection.

Environmental conditions such as high soil moisture, poor drainage, and high humidity are major factors driving disease spread. The fungus is highly persistent in the soil and can be easily disseminated through contaminated irrigation water, human activity, and the movement of infested nursery stock.

Prevention and management require strict sanitation practices, including the use of pathogen-free growing media and thorough cleaning of equipment. Protective measures include implementing proper irrigation management to avoid waterlogging and applying specific fungicides to suppress the fungal population in the soil.