Botryosphaeria canker

Systematic position and nature of the pathogen: Botryosphaeria quercuum is an ascomycete fungus within the order Botryosphaeriales. It is recognized as a significant plant pathogen capable of causing serious localized and systemic infections in the woody tissues of various tree species, leading to structural damage and vitality loss.

Diseases and host plants: This fungus is primarily associated with canker and dieback diseases. It affects various oak species (Quercus) and other broad-leaved trees, causing lesions that develop into bark necrosis, limb dieback, and potentially, the eventual death of the entire tree if the trunk is girdled by the expanding canker.

Biology and life cycle: The pathogen survives as mycelium or reproductive structures (pycnidia and perithecia) within infected woody tissues. Under warm and humid conditions, it releases spores that are disseminated by splashing rain, wind, or insects. These spores enter the host plant through wounds, natural openings, or bark fissures caused by environmental stress.

Conditions for development and harmfulness: Development is favored by high humidity and moderate to warm temperatures, typically between 20°C and 28°C. The pathogen thrives on trees weakened by drought, transplant stress, or poor soil conditions. Its harmfulness is manifested through the occlusion of vascular tissues, which restricts water and nutrient transport, leading to canopy decline.

Protection and control measures: Effective management of Botryosphaeria requires a multifaceted approach focused on prevention and sanitation:

• Prompt removal and destruction of infected branches to reduce local spore inoculum.
• Sterilization of pruning tools between uses to prevent the mechanical transmission of the pathogen.
• Application of protective fungicides on wounds after significant pruning or storm damage.
• Enhancement of tree vigor through proper irrigation, mulching, and balanced fertilization.
• Monitoring of tree health to detect early symptoms, such as oozing sap or cracked bark.