Dothiorella iberica

Systematic position and nature of the pathogen: Dothiorella iberica is a fungal pathogen classified within the Ascomycota phylum and the Botryosphaeriales order. It is recognized as an aggressive member of the Botryosphaeriaceae family, known for its ability to cause severe wood-decaying diseases in various perennial horticultural crops.

Host range and diseases caused: The fungus is primarily associated with grapevine trunk diseases, often contributing to the complex of symptoms leading to dieback. It also has a broad host range, infecting a variety of economically important trees, including almonds, walnuts, apple trees, and olives, causing necrotic lesions and internal wood discoloration.

Biology and life cycle: The pathogen survives as mycelium or fruiting bodies (pycnidia) within dead wood and infected pruning debris. Under favorable environmental conditions, including rainfall and high humidity, the fungus releases conidia. These spores are dispersed by rain splash and wind, infecting plants through wounds caused by pruning, mechanical damage, or environmental stressors.

Development conditions and impact: Dothiorella iberica thrives in moderate temperatures and high-moisture environments. Once inside the host, it colonizes the xylem vessels, obstructing water transport. This results in progressive dieback of branches, stunted growth, chlorosis, and, in severe cases, the sudden death of the entire plant, leading to significant yield losses.

Protection and control measures: Due to the systemic nature of the colonization, there is no curative fungicide treatment for established infections. Therefore, management focuses on preventive strategies:

• Sanitation: Removing and destroying heavily infected wood to reduce inoculum sources.
• Wound protection: Applying fungicides or sealing paints immediately after pruning.
• Tool sterilization: Disinfecting pruning equipment between plants to prevent pathogen transfer.
• Cultural practices: Minimizing plant stress through proper irrigation and balanced fertilization to improve natural defenses.