Dacrymyces stillatus

Dacrymyces stillatus is a species of jelly fungus belonging to the order Dacrymycetales. As a saprotrophic organism, it primarily decomposes dead woody material, but it can also colonize weakened or damaged living trees, as well as external timber structures such as fences, decking, and garden furniture, particularly in areas where moisture remains trapped.

The fungus affects both softwood and hardwood species, as well as processed timber used in landscaping and construction. It thrives by utilizing the moisture content within the wood fibers, which allows the mycelium to penetrate deep into the material, leading to the gradual degradation of its structural components, including cellulose and lignin.

The visual symptoms are characteristic and easily identifiable: the fungus produces small, bright yellow to orange gelatinous cushions or pustules. When environmental conditions change or the fungus matures, these structures lose their moisture, become tough, shriveled, and take on a dark red or brownish color. This cycle of expansion and contraction creates stress within the wood grain.

Environmental conditions play a critical role in the development and spread of Dacrymyces stillatus. High humidity levels, prolonged rainfall, and insufficient airflow around wood surfaces create the perfect conditions for spore germination and rapid fungal growth. These fungi are particularly aggressive in shaded areas where wooden structures do not have the opportunity to dry out properly.

Effective management requires a proactive approach centered on prevention. Essential measures include the application of professional-grade wood preservatives, regular painting or staining, and ensuring that timber does not remain in direct contact with wet soil. If an infestation occurs, affected areas should be physically removed, and the remaining healthy wood treated with appropriate fungicides to prevent re-colonization.