Rosellinia root rot

Rosellinia root rot is a devastating soil-borne fungal disease caused by species within the Rosellinia genus. This pathogen primarily attacks the root systems of various woody perennials, leading to the rapid decay of vascular tissues and eventual death of the host plant.

The disease poses a significant threat to many plantation crops, most notably Arabica coffee and Robusta coffee. It also affects a wide range of fruit-bearing trees, shrubs, and ornamental plants, making it a major concern for global agricultural biosecurity and farm management.

Common symptoms include chlorosis, wilting of leaves, and dieback of branches, often progressing rapidly across the plantation. Below ground, the roots exhibit white, fan-like mycelial mats that eventually develop into characteristic dark, brittle rhizomorphs, causing the inner root tissue to turn black and necrotic.

The development of the fungus is favored by warm, humid conditions, poorly drained soils, and the presence of buried organic debris, which provides a nutritional bridge for the fungus to spread. It persists in the soil for years, making it an extremely persistent and difficult pathogen to eradicate once established.

Integrated pest management (IPM) is essential for control. Effective strategies include:

• Rigorous removal and destruction of infected trees along with their root systems.
• Deep trenching to isolate patches of infection and prevent root contact.
• Improving soil drainage and aeration.
• Avoiding the use of fresh organic matter near the root zone.
• Applying preventive fungicidal treatments where local protocols allow.