Discina perlata

Discina perlata, commonly known as the pig's ear or shield-shaped disc, is an ascomycete fungus that predominantly acts as a saprotroph. While it is primarily associated with decaying wood, its presence in orchards or nursery environments can signal underlying issues with tree health, as it tends to colonize tissues weakened by physiological stress or environmental damage.

The causal agent is the Discina perlata fungus, which triggers the degradation of ligneous tissues. It primarily targets various broad-leaved trees, including birch, oak, and beech. The fungus operates by breaking down complex structural compounds in the wood, effectively acting as a decay agent that undermines the structural integrity of the affected plant host.

Symptoms of infestation are marked by the presence of brown, cup-shaped fruiting bodies appearing on or near the host. Internally, the wood shows signs of softening and loss of density. This often manifests as a reduction in the vigor of the tree, yellowing of foliage, and eventually, the structural failure of stems or branches due to severe internal wood rot.

Environmental conditions conducive to the development and spread of Discina perlata include high humidity, moderate spring temperatures, and the presence of abundant woody debris. The fungal spores are effectively disseminated by wind, rain, and insects, establishing themselves on exposed wood surfaces, pruning wounds, or existing bark fissures where the initial infection begins.

The economic harm is significant as the fungus compromises the long-term health and safety of tree stands. Protection and prevention strategies include:

• systematic removal of stumps and decaying woody material;
• proper sealing of pruning wounds with professional protective agents;
• maintenance of soil health and tree nutrition to prevent physiological decline;
• strict avoidance of bark damage during standard garden maintenance.