Prosthemium disease

Prosthemium disease is an infectious fungal condition affecting plants, caused by the imperfect fungi of the genus Prosthemium. This pathogen belongs to the group of bark and wood necrosis agents that primarily attack weakened woody species and shrubs. The disease is characterized by the progressive death of tissues, which, if not controlled, can lead to the loss of individual branches or even the entire plant.

The pathogen affects a wide range of broad-leaved trees and shrubs, including willow, birch, poplar, maple, and several fruit-bearing species. Specimens experiencing stress due to unfavorable environmental conditions, mechanical damage to the bark, or pest infestation are the most susceptible to infection, as these factors create entry points for fungal spores.

The key symptoms of the infection include the appearance of specific necrotic lesions on branches and trunks. In areas where the pathogen has penetrated, the bark darkens, cracks, and often exhibits peeling. As the mycelium develops under the epidermis, fruiting bodies (pycnidia) are formed, appearing as small bumps frequently arranged in clusters. Affected areas eventually dry out, causing the crown above the lesion to lose turgor and die off.

The development and spread of the infection are directly linked to hydrothermal conditions. Optimal conditions for spore germination include high humidity and moderate temperatures. Infection often occurs during spring or autumn, when spores are dispersed by rain droplets, wind, or insect vectors. Pre-existing wounds from pruning, hail, or sunscald significantly increase the risk of colonization by the fungus.

Control measures are based on a comprehensive approach and strict adherence to good agricultural practices. Prevention involves the following activities:

• Regular sanitary pruning and removal of infected branches, followed by safe disposal or burning.
• Disinfection of pruning wounds with pruning sealers or copper-based fungicides.
• Maintaining plant vigor through appropriate irrigation and nutrient management.
• Application of contact or systemic fungicides during periods when spore transmission is most likely.