Hymenochaete canker

Hymenochaete canker is a serious fungal disease caused by the pathogen Hymenochaete agglutinans. This fungus primarily attacks the bark and cambium of woody plants, leading to the formation of cankers that can eventually girdle branches or entire trunks, cutting off the tree's vital nutrient transport systems.

The disease is particularly known for affecting the Sweet Gum (Liquidambar) tree. While it can occur in various environments, the pathogen thrives in areas where young, vulnerable trees are exposed to high humidity and poor circulation, which facilitates the growth and spread of the fungal mats.

The primary symptoms include the development of dry, brownish or crust-like fungal growth that encases twigs or small trunks. Over time, the bark beneath these mats becomes necrotic and dies. Foliage beyond the cankered area will typically exhibit wilting, chlorosis, and premature senescence, often leading to the eventual death of the affected branch.

Transmission occurs primarily through wind and rain-splash dispersal of spores. These spores enter the tree through natural fissures, wounds caused by mechanical damage, or improper pruning cuts. Once established, the fungus grows actively under moist conditions, gradually encircling the host tissue and choking the flow of water and nutrients.

Effective management requires a proactive approach:

• Sanitary pruning of all infected branches at least 15-20 cm below the visible canker.
• Sterilization of pruning tools using alcohol or bleach solutions to prevent cross-contamination.
• Promoting overall tree vigor through proper watering and mulching to improve the tree's natural defense.
• Avoiding unnecessary bark injuries during landscaping or maintenance operations.