Anthracnose of elderberry

The causative agent of the disease is the fungus Colletotrichum sambucicola. This pathogen belongs to the group of fungi that cause anthracnose, a destructive disease characterized by localized necrotic lesions on various plant tissues, which eventually compromises the structural integrity and health of the elderberry bush.

The host range is primarily limited to various species of the genus Sambucus (elderberry). The fungus infects the foliage, petioles, and young green stems. In dense plantings or moist garden environments, the disease can spread rapidly throughout the crown, significantly impacting the aesthetic appeal and photosynthetic capacity of the plant.

Visible symptoms include the development of circular or irregular dark, sunken spots on leaves and stems. As the infection progresses, these spots often merge, and small acervuli (spore-producing structures) appear as tiny black dots on the lesion surfaces. This leads to leaf yellowing, premature defoliation, and in severe cases, the dieback of entire twigs and branches.

The development of Colletotrichum sambucicola is heavily dependent on environmental conditions, particularly high humidity and prolonged moisture on plant surfaces. Warm, wet springs and summers create the perfect environment for spore germination and infection. Rain splashes and wind play a crucial role in the dissemination of spores from infected plant debris to healthy tissues.

Effective management requires an integrated strategy to reduce inoculum levels and protect the plant. Key measures include removing and disposing of infected plant parts to minimize the source of spores, maintaining adequate air circulation around shrubs to promote rapid drying, and applying registered fungicides during periods of high disease pressure. Constant monitoring is vital for early detection and mitigation.