Fenestellaceae fungi

The first noticeable sign of infection is the appearance of necrotic zones on the bark of branches and trunks. In areas where the fungus develops, the bark takes on a dark color, gradually dries out, and may crack.

Upon close inspection, small, barely visible dots can be found on the surface of the affected areas; these are the fruiting bodies of the fungus protruding through the bark epidermis. They may be grouped into small cushions.

As the disease progresses, the dieback of individual branches where infection foci are located is observed. This leads to a gradual thinning of the tree crown.

If the infection affects the main trunk, deep necrosis can develop, preventing normal sap flow. Leaves on affected branches turn yellow prematurely, lose turgor, and fall off.

A characteristic symptom is also the peeling of bark in infected areas, exposing the damaged cambial zone. In severe cases, the complete death of a crown section or the entire tree is observed.

The disease is caused by fungi of the Fenestellaceae family, belonging to the order Pleosporales. These are primarily saprotrophic or weakly pathogenic organisms frequently found on decaying tissues of woody plants.

Biologically, these fungi are ascomycetes that develop within the bark and wood of affected crops. They are capable of forming specific fruiting bodies, known as pseudothecia, which are embedded in the substrate of the host plant.

The pathogen's life cycle is closely linked to the weakening of the plant's immune system. Under favorable conditions, the fungus begins to actively develop mycelium, penetrating living tissues through cracks, wounds, or natural openings.

Fungi of this family often act as secondary infections, colonizing areas already damaged by other stress factors. Their development leads to further degradation of the bark tissues.

Sporulation occurs mainly during the spring-autumn period, when air humidity is optimal for the spread of conidia and ascospores. Spores are dispersed to healthy branches by wind and rain splashes.

The primary condition for the active development of Fenestellaceae is high air humidity and moderate temperatures. Excess moisture creates an optimal environment for spore germination.

The general state of the plant has a significant impact on the spread of the disease. Trees experiencing nutrient deficiencies or soil moisture deficits are much more susceptible to infection.

Mechanical damage to the bark caused by hail, insects, or improper pruning serves as a "gateway" for the initial infection. Tools that have not been disinfected also contribute to spore dispersal.

Dense, poorly ventilated plantings create moisture stagnation, which triggers the accumulation of the infectious background. Lack of sunlight slows down the drying of bark after rain, prolonging the pathogen's activity period.

Cold winters with sharp temperature fluctuations can lead to frost cracks, which are often colonized by fungi of this family in the following spring.

The harmfulness of Fenestellaceae fungi lies in the disruption of the tree's physiological processes. Damage to conductive tissues leads to weakened growth and reduced crop productivity.

In horticulture and forestry, the pathogen can lead to the premature death of valuable specimens. The reduction in wood quality and its commercial appearance is a serious economic loss.

Foci of the disease can persist in a garden for years, constantly lowering the immunity of trees and preparing the ground for infection by more dangerous parasites. This makes fighting the fungus a chronic task.

The gradual dieback of skeletal branches deforms the crown, which negatively affects the ornamental quality of landscaping plants. Additionally, such trees become a source of spores for the entire area.

With high intensity of infection, the tree may die within a few seasons. Weakened trees also become more attractive to secondary pests, such as wood-boring insects.

Prevention begins with proper care aimed at maintaining a high level of plant immunity. Timely pruning and balanced fertilizer application are essential.

All damaged, dead, or infected branches must be removed and destroyed immediately by burning them away from the site. Plant debris should not be left under the tree canopy.

After pruning, cut surfaces should be treated with grafting wax or special fungicidal pastes to prevent spores from entering fresh wounds.

Preventive spraying with copper-based fungicides during the dormant period (early spring or late autumn) effectively reduces the infectious background in the garden and hinders the development of fungal spores.

• Regular sanitary pruning.
• Disinfection of garden tools.
• Whitewashing of trunks with lime and antiseptics.
• Ensuring optimal air circulation in the crown.
• Timely fertilization to increase tree resistance.