Didymella cane blight

Didymella cane blight, caused by the fungus Didymella applanata, is a common and destructive fungal disease primarily affecting raspberry and blackberry crops. The pathogen lives and reproduces on the plant's stems, causing lesions that eventually compromise the plant's overall vascular system.

The fungus typically attacks plants from the genus Rubus. It overwinters in infected canes and leaf debris, making it a persistent problem in plantations where sanitation measures are neglected. The disease is known to significantly weaken the canes, often leading to total loss of fruit production.

Visible symptoms include dark purple or reddish-brown spots appearing at the base of the leaves and nodes. As the infection progresses, these lesions expand, and the stems develop a silvery-gray appearance with noticeable cracking in the epidermis, which often results in the death of buds.

The development of this disease is heavily influenced by environmental conditions, particularly high humidity, frequent rainfall, and stagnant air. The spores of the fungus are dispersed through rain splashes and wind, making rapid spread very likely during wet, warm summers.

Preventive strategies are essential for effective management. This includes strictly removing infected canes after harvest, avoiding overhead irrigation, and maintaining proper plant spacing to improve air circulation. Fungicidal treatments should be applied during the early growth stages to suppress spore formation.

• Sanitary pruning of diseased canes
• Improvement of plantation airflow
• Application of fungicides at leaf-out
• Selection of resistant plant varieties