Raspberry spur blight

Didymella_applanata_(4)

Raspberry Spur Blight

Raspberry spur blight, caused by the fungus Didymella applanata, is a common disease affecting raspberry plants. This fungal pathogen primarily targets the canes and spurs of raspberry bushes, leading to reduced fruit yield and overall plant health.

Symptoms

Symptoms of raspberry spur blight typically manifest as dark purple to black lesions on the canes and spurs of infected plants. These lesions may also exhibit a characteristic white powdery growth in humid conditions. As the disease progresses, the affected tissue may become brittle and die back, ultimately impacting the plant's ability to produce healthy fruit.

Disease Cycle

The fungus responsible for raspberry spur blight overwinters in infected plant debris and can spread through splashing water or physical contact. In the spring, the fungus produces spores that are carried by wind or rain to healthy raspberry plants, initiating new infections. Warm and humid conditions favor the development and spread of the disease.

Management

Effective management of raspberry spur blight involves a combination of cultural practices and chemical control methods. Pruning out infected canes and spurs during the dormant season can help reduce the disease's spread. Additionally, applying fungicides at the appropriate times can help protect healthy plants from infection.

Prevention

To prevent raspberry spur blight, it is essential to practice good sanitation in the raspberry patch by removing and destroying infected plant material. Planting disease-resistant raspberry cultivars and providing adequate spacing between plants to promote air circulation can also help reduce the risk of infection.