Marquandomycosis

The first visual sign of infestation is the appearance of specific spots on leaves, which eventually acquire a brown or dark-brown shade. A characteristic chlorotic border is often observed around the edges of the spots.

Deep necrotic ulcers form on shoots and young branches, leading to tissue deformation and disruption of the normal movement of nutrients throughout the plant.

Under high humidity conditions, a weak mycelial coating with a grayish or white color may appear on the affected areas, indicating an active phase of fungal sporulation.

Severe infestation is accompanied by premature leaf drop, which significantly weakens the plant's immune system and reduces its ability to prepare for the winter period.

• Darkening and necrosis of bark areas.
• Appearance of necrotic spots on the leaf blade.
• Curvature of young shoots.
• Stunted growth and overall development of the crop.

The causative agent of this disease is the microscopic fungus Marquandomyces. It belongs to the group of ascomycetes and is a specialized pathogen capable of affecting mainly woody and shrubby species in temperate climates.

The fungus leads a parasitic lifestyle, penetrating plant tissues through micro-damages in the bark or stomata. The pathogen's mycelium actively grows in the intercellular spaces, gradually destroying the host's tissue structure.

Reproduction occurs asexually through the formation of conidia, which are dispersed by wind, raindrops, or insects to healthy parts of the plant. The spores possess high resistance to unfavorable external factors.

The life cycle of Marquandomyces may also include a sexual stage, providing genetic diversity and more successful adaptation of the fungus to environmental conditions, which makes the pathogen extremely resilient.

Studying the biological characteristics of this fungus is a key step in developing effective chemical and biological protection systems for orchards and nurseries against this disease.

Warm and humid weather promotes the development of Marquandomyces. The optimal temperature range for spore germination is from +18 to +24 degrees Celsius at high relative air humidity.

The presence of liquid moisture on the surface of leaves for a long time significantly accelerates the process of tissue infection, providing the pathogen with ideal conditions for colonization.

Dense plantings, lack of proper pruning, and poor crown aeration contribute to moisture stagnation, which multiplies the risk of rapid infection spread across the entire area.

Weakened plants that have suffered from pests, lack of nutrients, or mechanical damage become the most vulnerable targets for this pathogen.

Secondary infection foci often arise in places where plant debris has not been timely removed or disposed of, as the fungus is capable of overwintering in fallen leaves and bark residues.

The main damage caused by marquandomycosis lies in the loss of the leaf's photosynthetic surface, which leads to a decrease in the accumulation of organic matter and the depletion of energy reserves in the plant.

When young shoots are affected, they wither, which significantly deforms the crown and negatively impacts the decorative qualities or yield of the fruit crop.

The chronic course of the disease significantly lowers the winter hardiness of plants, making them sensitive to sudden temperature changes and freezing during the winter-spring period.

In nurseries, this infection can lead to mass mortality of seedlings, causing serious economic losses for agricultural enterprises and private producers of planting material.

Prolonged infestation of shrubs or trees by this fungus without proper control leads to their gradual degradation and final death within a few seasons.

The basis of protection is the agrotechnical method, which includes regular sanitary pruning of infected branches followed by their burning or deep burial in the soil.

It is important to follow an optimal planting scheme to ensure good crown ventilation, which prevents the creation of a microclimate favorable for the development of fungal spores.

The use of systemic and contact fungicides at the early stages of disease manifestation allows for the effective stopping of spore spread and the protection of healthy plant tissues.

Conducting preventive treatments with copper-based preparations in early spring helps significantly reduce the infectious background and prevent primary infection of young leaves.

Balanced plant nutrition with sufficient potassium and phosphorus fertilizers increases the natural resistance of crops to the influence of Marquandomyces and other pathogens.