Cylindrocladium parvum

Cylindrocladium parvum is a soil-borne fungal pathogen belonging to the Kingdom Fungi. It is primarily recognized for its role in causing significant diseases in forest nursery settings and ornamental plant production. As a destructive agent, it primarily attacks the roots and stems of young plants, leading to severe economic losses in professional horticulture.

This pathogen is known to cause various diseases, including root rot, stem blight, and foliage spotting. It affects a wide variety of plants, including conifers and various broadleaf ornamental shrubs. The primary damage manifests as systemic wilting followed by tissue necrosis, which can wipe out entire batches of seedlings if left untreated.

The biology of Cylindrocladium parvum is characterized by the production of abundant conidia and resilient chlamydospores. These resting structures allow the fungus to survive in infested soil for extended periods even in the absence of host plants. Dissemination typically occurs through contaminated water splash, nursery tools, infected plant debris, and movement of soil particles.

Development and spread are favored by high humidity and warm temperatures, typically ranging between 20°C and 28°C. Greenhouse environments with poor air circulation and excessive irrigation provide an optimal medium for the fungus to penetrate plant tissues and spread rapidly between adjacent plants, often leading to rapid decline in crop quality.

Effective management and control strategies are essential for nursery health:

• Strict sanitation protocols for tools, benches, and trays.
• Implementation of high-quality, sterilized growing media.
• Regulation of irrigation to avoid excessive soil moisture.
• Application of targeted fungicides, such as prochloraz or carbendazim-derivatives.
• Immediate removal and disposal of symptomatic plants to prevent sporulation.