Nectria canker

Nectria canker is a fungal disease caused by the ascomycete Nectria inventa (often associated with its anamorph Acremonium butyri). This pathogen acts as a necrotrophic parasite, invading the host tissues and triggering significant structural degradation of the plant's vascular and cortical systems.

This fungus primarily targets woody ornamental trees, fruit orchards, and occasionally indoor crops. It acts as an opportunistic pathogen, commonly colonizing tissues that have been previously weakened by environmental stressors like frost, drought, or mechanical wounds caused by pruning or harvesting tools.

Characteristic symptoms include the development of depressed, necrotic lesions on branches and stems. Over time, the bark surrounding these areas cracks or peels back. Under high humidity conditions, characteristic fruiting bodies emerge on the surface of the lesions, leading to shoot dieback and, in severe cases, the death of the entire plant structure.

The spread and development of the disease are highly dependent on high humidity and prolonged moisture. Spores are disseminated via wind currents, rain splash, and contaminated gardening tools. The fungus remains viable in infected wood, serving as a primary source of inoculum that can infect new plant tissues during periods of vulnerability.

Effective management and prevention of Nectria inventa require a integrated pest management approach:

• Strict sanitation protocols, including the immediate removal and destruction of diseased wood.
• Disinfecting all pruning tools between cuts to prevent mechanical transmission.
• Applying protective fungicides or sealant pastes to large wounds to prevent spore colonization.
• Maintaining optimal plant vigor through balanced fertilization and proper irrigation management.