Diaporthe necrosis

Diaporthe necrosis, caused by the fungal pathogen Diaporthe cytosporella, is a destructive disease affecting various woody plants and shrubs. As a specialized parasite, the fungus primarily invades the host through bark wounds, frost cracks, or pruning cuts, compromising the tree's vascular system and overall structural integrity.

The host range of this pathogen includes many species of fruit and ornamental trees. The fungus acts by colonizing the bark and cambium, progressively killing the affected tissue. Over time, the infection can spread along the branches, leading to dieback and significantly reducing the host's vitality and agricultural productivity.

Symptoms are characterized by localized bark lesions that become sunken, discolored, and necrotic. As the disease advances, the bark often develops cracks and begins to slough off. During periods of high humidity, small black fruiting bodies, known as pycnidia, may emerge through the bark, indicating active spore production and potential for further spread.

The development of Diaporthe cytosporella is closely tied to environmental conditions, particularly high humidity and moderate temperatures. Moisture facilitates the discharge of spores, which are then disseminated by wind, rain splashes, or contaminated pruning tools. Stressed plants, whether from drought or poor soil management, are notably more susceptible to colonization.

Effective management requires a multi-faceted approach. Preventive measures include regular sanitary pruning to remove infected wood, which must be destroyed away from the planting site. Furthermore, sterilizing tools between cuts, sealing pruning wounds with protective coatings, and maintaining optimal plant health through balanced fertilization and irrigation are essential to minimize infection risks.