Aspergillus ustus

During visual inspection of affected areas, especially on seeds and plant debris, pronounced sporulation is visible. In high humidity conditions, the substrate surface becomes covered with a dense layer of spore mass.

Internal plant tissues often undergo degradation due to Aspergillus ustus invasion. A change in color of the affected areas is observed, which turn dark due to the enzymatic activity of the fungus.

A characteristic sign is a specific earthy or dusty odor accompanying the active growth of colonies. This is a result of the fungus secreting metabolites during its feeding process.

When stored grain is affected, a process of self-heating occurs in the mass. This leads to the loss of commercial quality, the appearance of spots on the grain hulls, and a decrease in seed germination.

The causative agent of the disease is the microscopic fungus Aspergillus ustus, which belongs to the saprotrophic group with pronounced parasitic properties. This pathogen is a cosmopolitan species found in many climatic zones.

The fungus reproduces via conidia, which are easily carried by air currents over significant distances. The pathogen's mycelium can penetrate deep into plant tissues through micro-cracks or natural openings.

The biology of Aspergillus ustus is closely related to its high ability to adapt to various environments. It is a facultative parasite capable of transitioning from saprotrophic feeding to infecting living tissues.

The pathogen is characterized by high resistance to various environmental factors. Its spores maintain viability in the soil and on plant residues for extended periods.

The fungus has the ability to secrete a wide range of enzymes that break down plant polymers. This allows the pathogen to rapidly colonize organic substrates, including weakened plants.

The main factor promoting the development of the disease is high relative humidity. Optimal levels for active fungal sporulation range from 70 to 90 percent.

Temperature plays a crucial role: Aspergillus ustus develops actively within a wide temperature range, though values from +20 to +30 degrees Celsius are considered the most favorable.

Poor ventilation in warehouses or overly dense crops in the field create a microclimate that facilitates the rapid spread of infection. Stagnant moisture is the main trigger.

The presence of surface damage on plants, caused by pests or mechanical impact, significantly facilitates the penetration of the pathogen into the tissues.

Adherence to agronomic practices, such as timely grain drying and humidity control in storage facilities, is critical for suppressing the activity of this fungus.

The main harm lies in the reduction of both the quality and quantity of agricultural crop yields. The fungus causes rot, rendering products unsuitable for further use.

In storage conditions, Aspergillus ustus causes spoilage of commercial grain stocks. It destroys nutrients and accumulates fungal metabolic products, making the produce potentially toxic.

Infection of planting material leads to a sharp decrease in germination energy and seedling vigor. This results in sparse emergence and stunted plant development.

The fungus is capable of producing mycotoxins, which pose a serious danger to both animals and humans if contaminated raw materials are consumed.

Economic losses are composed of direct crop losses, costs for facility fumigation, and the necessity of additional expenses for disinfecting planting material.

Prevention begins with following crop rotation and thorough cleaning of fields from plant residues, which serve as an infection reservoir during the off-season.

The use of resistant varieties and high-quality treated planting material significantly reduces the risk of primary pathogen infection.

An important measure is moisture control during crop storage. Timely drying and proper ventilation prevent the development of mold fungi in grain heaps.

When chemical protection is necessary, broad-spectrum fungicides are applied. Products must be used strictly in accordance with regulations and application rates.

• Regular disinfection of storage facilities.
• Optimization of crop stand density.
• Timely management of insect pests.