Rigidoporus

Rigidoporus is a genus of fungi belonging to the Polyporaceae family, responsible for causing severe white rot diseases in perennial woody plants. The most economically significant species, Rigidoporus microporus, is a notorious root pathogen, particularly devastating to rubber tree plantations and various forest species in tropical climates.

The disease is caused by a soil-borne fungus that infects healthy trees through direct root-to-root contact or via fungal spores. Once inside, the fungus colonizes the root system and begins to decompose wood components, primarily lignin and cellulose, which creates the classic white, fibrous decay characteristic of white root rot.

Susceptible crops include a wide range of fruit-bearing trees and timber species. The pathogen thrives in environments with high rainfall, warm temperatures, and acidic soils, where it can remain dormant on decaying stumps and woody debris, acting as a permanent inoculum source for new plantings.

Symptoms often go unnoticed until the tree shows signs of severe stress. Common indicators include yellowing of leaves, premature leaf drop, and dieback of the crown. Upon examination, the roots display white mycelial strands, and fruiting bodies (brackets) often appear at the base of the trunk as the infection advances into the vascular tissues.

• Stump removal and site sanitation before establishing new plantations.
• Implementation of quarantine zones around infected trees to prevent root contact spread.
• Applying systemic fungicides to the surrounding soil as a protective barrier.
• Improving soil drainage to discourage the spread of water-borne fungal spores.

The impact of Rigidoporus is profound, leading to significant tree mortality and economic losses in commercial forestry and agriculture. Effective control requires a long-term strategy centered on integrated pest management, emphasizing cultural practices that minimize the presence of woody substrate in the soil where the fungus thrives.