Cylindrocladiella parva

Cylindrocladiella parva is a fungal pathogen belonging to the order Hypocreales, widely recognized for causing root and stem base diseases in various plants. It functions primarily as a soil-borne fungus, capable of surviving on organic debris and in infested soil for extended periods, which makes it a persistent challenge for commercial nursery growers and greenhouse operations.

This pathogen exhibits a broad host range, focusing mainly on young plants and seedlings. It commonly affects coniferous and broad-leaved tree species in forestry nurseries, as well as several ornamental plants and eucalyptus varieties. The ability to attack the vascular system of young, vulnerable plants makes it particularly destructive in high-density cultivation environments.

Symptoms of an infection include severe root necrosis, where roots lose their firmness and turn brown or black. As the pathogen advances toward the root collar, visible lesions or girdling can occur, severely restricting water and nutrient uptake. Above-ground symptoms usually manifest as wilting, yellowing (chlorosis), and eventual drying out of the foliage, leading to sudden plant death.

Development and spread of the fungus are heavily dependent on environmental conditions, particularly high moisture levels and poor soil aeration. The pathogen thrives in damp environments and can easily disseminate through irrigation water, contaminated potting media, and even through the movement of infested tools or infected plant stocks. High humidity within greenhouses provides an ideal microclimate for the fungus to multiply.

The economic impact of Cylindrocladiella parva is high, as it can cause significant seedling mortality and failure in production cycles. To minimize damage and ensure plant health, a robust integrated pest management approach is essential:

• Sterilize all growing media and equipment prior to sowing or propagation.
• Maintain optimal drainage to prevent waterlogging, which favors fungal proliferation.
• Implement strict sanitation practices, including the removal of infected plants.
• Apply preventative soil fungicides to control outbreaks and protect vulnerable seedling stages.