Trichoderma rot

Trichoderma rot is a fungal disease caused by the saprotrophic fungus Trichoderma viride. While this organism is frequently employed as a biological control agent against other plant pathogens, it can act as a decay-causing agent under specific conditions, particularly in compromised plant tissues or stored harvested crops.

The primary hosts for this disease include various species of Citrus. The fungus frequently targets fruits during post-harvest storage, especially when they are bruised or have skin abrasions. Additionally, seedlings in greenhouses can be susceptible if the growing media remains excessively damp for prolonged periods.

Symptoms are characterized by the development of fluffy, initially white or yellowish mycelial growth. As the fungus produces large quantities of conidia, the colonies turn a distinct, bright green color. Beneath the fungal mat, the host tissue turns soft, watery, and eventually collapses, often accompanied by a musty, earthy odor.

Development and spread are primarily driven by high humidity levels and poor ventilation within storage facilities. The spores of Trichoderma viride are highly resilient and easily dispersed via air currents, splashing water during irrigation, or contaminated tools and packaging materials. Damage to the plant cuticle is the most common entry point.

Management and prevention focus on maintaining optimal post-harvest storage conditions. Key measures include:

• Reducing ambient humidity in storage rooms.
• Ensuring proper airflow and circulation.
• Careful handling of produce to minimize bruising.
• Sanitizing containers and equipment to remove fungal spores.