European fruit tree canker

European fruit tree canker is a destructive fungal disease caused by the pathogen Nectria galligena. It primarily affects the woody parts of deciduous fruit trees, causing severe necrosis of the bark and cambium, which eventually leads to the formation of persistent, expanding cankers.

The most susceptible hosts are pome fruits, particularly apple trees and the common pear. The fungus gains entry into the plant tissues through wounds such as leaf scars, pruning cuts, frost cracks, or mechanical damage caused by insects or harvesting equipment.

Symptoms are categorized into open and closed cankers. Open cankers exhibit a sunken appearance with concentric rings of callus tissue surrounding the necrotic area. Closed cankers are characterized by bark splitting and bulging. During moist conditions, small white or red fruiting bodies of the fungus emerge near the edges of the canker.

The development and spread of the pathogen are heavily influenced by environmental factors, particularly moisture and temperature. Spores are dispersed mainly by rain splashes and wind during wet weather. Autumn, when leaf scars are exposed, is considered the most critical period for the initial infection of the season.

If left unmanaged, the disease causes significant economic loss due to branch dieback and reduced fruit quality. Effective control strategies include rigorous pruning of infected wood, immediate disinfection of pruning tools, and the application of protective fungicide treatments during dormancy and after leaf fall to protect vulnerable wound sites.

• Perform regular pruning to remove infected wood during dry weather.
• Apply wound paints or protective pastes immediately after large cuts.
• Ensure proper tree nutrition to improve natural disease resistance.
• Remove and destroy all cankered prunings from the orchard environment.