Dacrymycetaceae fungi

The family Dacrymycetaceae comprises basidiomycete fungi primarily known as saprotrophs that inhabit decaying wood. While they are often viewed as decomposers in forest ecosystems, in orchard and landscape management, they serve as indicators of wood degradation and potential structural instability in trees that have been compromised by wounds or abiotic stress.

The causative agents are various species within this family, most notably Dacrymyces stillatus. These fungi induce a type of brown rot, where they specifically target cellulose and hemicellulose while leaving the lignin mostly intact. This process significantly alters the chemical composition of the wood, leading to structural failure.

These fungi affect a variety of woody plants, including conifers and broad-leaved species. They are frequently found on orchard trees, particularly on older specimens that have sustained mechanical damage, sunscald, or improper pruning wounds. The presence of the fungus is often a sign that the tree is already struggling with internal decay or lack of vigor.

Symptoms are easily identifiable by the gelatinous, yellow to orange fruiting bodies that appear on the surface of bark or wood. As they dry, these structures harden and become dark brown. Internally, the wood exhibits deep brown discoloration, shrinkage, and characteristic cracking into small, irregular cubes as the decay progresses.

Development and spread are favored by high humidity, poor aeration, and the presence of moist, dead organic matter. Spores are dispersed through wind and splashing rain, settling in crevices or wound sites. The economic impact is primarily related to the structural loss of timber or the premature death of ornamental and fruit-bearing trees due to branch breakage.

• Sanitize by removing and burning dead or decaying branches.
• Treat all major pruning wounds with appropriate fungicides or protective sealants.
• Maintain tree vigor through proper fertilization and irrigation to improve natural defense.
• Avoid damaging the bark of trees during lawn maintenance or mechanical operations.

Management strategies focus on prevention and the maintenance of tree hygiene. By keeping trees in good physiological health and ensuring that any injuries are promptly covered, the risk of colonization by Dacrymycetaceae is significantly reduced. Regular monitoring of trees for fungal growth is essential to prevent extensive decay before it leads to safety hazards.