Tripe fungus

Tripe fungus (Auricularia mesenterica) is a basidiomycete fungus known in arboriculture for causing white rot in wood. Acting as a facultative parasite, it predominantly colonizes dead or stressed woody plants, using its mycelium to break down complex lignin and cellulose structures, effectively turning strong wood into brittle, decayed matter.

The host range of this pathogen includes various broad-leaved trees, notably fruit trees like apple and plum, as well as landscape species such as elm, beech, and poplar. The infection usually gains entry through compromised bark, pruning wounds, frost cracks, or any area where the natural protective layer of the tree is absent or damaged.

Diagnostic symptoms are clearly visible when the fruiting bodies emerge on the bark surface. These appear as irregular, jelly-like, resupinate brackets that often fuse together. The upper surface is typically hairy and greyish-brown, while the fertile underside is purplish or brownish with a distinct wrinkled, veined appearance. Internally, the wood loses structural integrity and exhibits signs of bleached, soft decay.

The development of the fungus is strictly moisture-dependent, thriving in high-humidity environments and moderate temperatures. Wind-borne spores and insect vectors facilitate the spread of the pathogen, allowing it to land on vulnerable wooden surfaces. Once established, the fungus can survive for long periods, slowly consuming the internal heartwood of the host plant.

The impact of this disease can be devastating, leading to structural instability and eventual failure of affected branches or entire trees. Effective management strategies include:

• Performing professional pruning to minimize open wounds and applying protective sealants to cuts.
• Ensuring proper canopy ventilation to reduce localized humidity.
• Regularly inspecting trees for fungal brackets and removing infected wood immediately.
• Maintaining tree vigor through proper irrigation, fertilization, and site management.