Coryneum megaspermum

Coryneum megaspermum is a fungal plant pathogen responsible for causing necrotic diseases in woody plants. It primarily targets the bark and cambial layers of trees, disrupting nutrient transport and leading to the development of localized cankers that can eventually girdle entire branches or trunks.

This pathogen commonly affects a variety of broad-leaved and fruit-bearing trees. Susceptible species often show significant signs of decline when grown in environments with high humidity or poor air circulation, which are characteristic of dense nursery stands or overcrowded orchards.

Initial signs of the infection appear as distinct spots or sunken necrotic lesions on the younger branches. As the disease progresses, these lesions expand into elongated cankers, often causing the bark to crack or bleed exudates. Advanced stages of infection result in leaf wilting, twig dieback, and stunted growth of the entire plant.

The development and spread of Coryneum megaspermum are highly dependent on environmental conditions, particularly moisture and temperature fluctuations. During wet spring and autumn months, conidia are dispersed by wind-blown rain and contaminated tools, allowing the fungus to infect new hosts through cracks or pruning wounds.

Effective management and prevention of the disease require a holistic strategy:

• Pruning and removing all infected branches during the dormant season.
• Sterilizing all pruning tools with alcohol or bleach after each use.
• Applying copper-based fungicides to protect vulnerable bark surfaces.
• Maintaining proper spacing between trees to improve ventilation and reduce humidity.