Godronia canker

Godronia canker is a fungal disease caused by the pathogen Godronia urceolus, which manifests primarily as a stem blight on various woody shrubs. It is a significant concern for cultivators of berries, particularly highbush blueberries, where it can drastically reduce crop yields and plant longevity.

The fungus acts as a necrotrophic pathogen, invading the cortex and phloem of the plant. It exploits bark fissures and wounds, allowing the mycelium to penetrate the inner tissues. Once established, the fungus produces toxins that cause the collapse of cells, resulting in the characteristic lesions and cankers on the stems.

The disease is easily identified by the appearance of discolored, reddish-brown patches on current or older stems. These lesions eventually enlarge into oval-shaped cankers with a dark red border. Under favorable moisture conditions, the fungus produces small, cup-shaped fruiting bodies known as apothecia on the surface of the dead tissue.

Environmental conditions play a critical role in the epidemiology of Godronia urceolus. High relative humidity and cool temperatures are favorable for sporulation and subsequent infection. The disease spreads primarily through splash-dispersal of spores during rainy weather, making high-density plantings particularly vulnerable.

Integrated pest management is essential for controlling this fungal infection.

• Pruning out all infected canes as soon as symptoms appear.
• Sanitizing pruning shears to prevent cross-contamination.
• Improving airflow within the canopy through proper spacing and pruning.
• Applying registered fungicides based on the plant's growth stage and infection history.