Diplodia canker

Diplodia canker is a destructive disease affecting oak trees, caused by the fungus Diplodia corticola. This pathogen belongs to the Botryosphaeriaceae family and is known for causing significant damage to the bark and inner tissues of the host. The disease is classified as a vascular and cortical infection, which disrupts the tree's ability to transport water and nutrients.

The primary hosts of this fungus are various oak species, including cork oak and deciduous oaks. The disease is particularly problematic in regions experiencing climatic instability. Trees under environmental stress, such as prolonged drought or extreme heat, are significantly more susceptible to infection by this opportunistic pathogen.

Symptoms of Diplodia infection typically manifest as lesions or cankers on the stems and branches. These areas often appear darkened and sunken compared to healthy tissue. As the fungus colonizes the wood, it leads to branch dieback, leaf wilting, and, in severe cases, the mortality of the entire tree. Sap bleeding from the infection site is also a common observation.

The environmental cycle of the fungus is heavily dependent on moisture and temperature. Spores (conidia) are dispersed by rain splash and wind, landing on bark crevices or wounds. Once the fungus enters the host through these openings, it grows through the cortical layers. Warm, humid conditions are optimal for the pathogen to establish and spread to adjacent tissues.

Management of the disease focuses on reducing inoculum pressure and improving tree vigor. Essential strategies include regular inspection of plantations to detect early signs of infection. Infected branches should be pruned back to healthy wood, ensuring tools are disinfected between cuts. Protecting trees from physical bark damage and insect infestations is crucial for effective prevention.