Pyrenothricaceae

Pyrenothricaceae is a family of fungi belonging to the class Dothideomycetes. While in a strict agronomic sense these organisms are often classified as epiphytes or lichenized fungi, under specific environmental conditions, they can act as pathogens or associated agents that compromise the overall vigor and physiological status of the host plant.

The causal agent is a microscopic fungus that primarily colonizes the surface of plant vegetative organs. The disease type is typically characterized as superficial colonization, which, when the plant's immune system is weakened, can lead to necrotic lesions on the epidermis, interfering with essential processes such as photosynthesis and transpiration.

These fungi predominantly affect the bark of trees, shrubs, and the foliage of evergreen plants. They pose a particular risk in regions with high humidity levels, where the development of mycelium on the surface of leaves or stems occurs most intensively, creating a conducive environment for secondary infections.

Symptoms of infestation manifest as the formation of dark coatings, spotting, or specific scale-like structures on the tissue surface. Unlike deep-seated necrosis, these signs often appear as crusts; however, beneath them, the plant tissue may undergo chlorosis and subsequent necrosis due to the obstruction of stomata.

Conditions for development and control measures include:

• High relative humidity and frequent precipitation.
• Overcrowded plantings that prevent adequate crown ventilation.
• Sanitary pruning and the removal of infected plant debris.
• Application of broad-spectrum fungicides in cases of severe outbreaks.
• Regular fertilization and care to enhance the plant's natural immune defense.