White root rot

The disease is caused by the basidiomycete fungus Scytinostroma galactinum. This pathogen specializes in attacking the root systems and the root collar of woody plants, causing decay that disrupts vital transport processes within the plant tissue.

This pathogen has a wide host range, posing a significant threat to various agricultural and orchard systems. Key hosts include Citrus species, Apple (Malus domestica), Red raspberry (Rubus idaeus), and Cacao plantations.

The primary clinical signs include foliage yellowing, reduced vigor, and progressive dieback of branches. Below ground, the roots exhibit a distinct white mycelial mat covering the surface, leading to the disintegration of woody tissues and the development of a brittle, white-rotted texture in the root core.

Favorable conditions for the development and spread of the pathogen include high soil moisture, poor drainage, and limited aeration. The fungus can persist in the soil for extended periods on colonized debris, facilitating long-term infection cycles and transmission to healthy root systems upon contact.

Economic losses can be substantial, as affected plants often decline over several years before death occurs. Protection and control strategies focus on sanitation, such as removing infected trees with their root masses, ensuring proper soil drainage, and utilizing certified, pathogen-free planting stock to prevent the introduction of the disease.