Cylindrocarpon root rot

Cylindrocarpon root rot is a serious plant disease caused by the fungal pathogen Cylindrocarpon olidum. This fungus, frequently associated with the sexual stage Neonectria radicicola, acts as a soil-borne parasite that primarily targets the vascular and root tissues of its hosts, leading to significant physiological decline.

The pathogen has a wide host range, affecting various agricultural and horticultural species. Crops such as ginseng, cucumbers, tomatoes, and ornamental nursery stocks are particularly susceptible. The fungus is especially problematic in greenhouse environments where consistent moisture and controlled temperatures facilitate rapid spread.

Symptoms of the disease initially manifest in the root system as brownish, water-soaked lesions that eventually progress to extensive necrotic decay. As the root integrity is compromised, the plant shows signs of nutrient deficiency, such as leaf chlorosis, stunted growth, and sudden wilting. If left untreated, the entire root system may collapse, leading to irreversible plant mortality.

The development of Cylindrocarpon olidum is heavily dependent on soil moisture levels and poor soil aeration. High humidity and cold, wet conditions in the early stages of growth favor fungal proliferation. The pathogen survives in the soil as chlamydospores or mycelium, allowing it to persist for years until favorable conditions permit new infections to occur.

Controlling this disease requires an integrated management approach. Growers should prioritize the use of sterilized soil and disease-free plant material. Improving soil drainage is critical to prevent the moisture levels required for the fungus to thrive. In cases of severe outbreaks, chemical control using systemic fungicides or the application of biological control agents (such as beneficial bacteria or fungi) is necessary to mitigate crop loss.