Aspergillus ustus

Aspergillus ustus is a filamentous fungus belonging to the Ascomycota division, known to cause diseases in various agricultural products. Primarily recognized as a post-harvest pathogen, it is responsible for the degradation of stored grain and seeds. Its ability to thrive in diverse environments makes it a significant concern for global agricultural safety and food security.

This pathogen commonly attacks crops such as wheat, corn, peanuts, and soybeans. In the field, it can affect plants weakened by abiotic stress or mechanical damage. However, its primary impact is seen in storage facilities where it colonizes seed lots, causing significant economic losses by reducing both the commercial value and the germination potential of the seed material.

Symptoms of Aspergillus ustus infection appear as a characteristic grayish-brown to dull olive-colored mold growth on the surface of the affected crops. Over time, the infected material may show signs of decay, discoloration, and a distinct musty odor. The production of specific mycotoxins by the fungus poses health risks, making the contaminated crops unsuitable for food or animal feed.

The development of this disease is heavily influenced by high relative humidity and elevated temperatures. The fungus prospers when moisture content in grain exceeds safe thresholds, typically above 14%. Because the spores are ubiquitous in soil and air, the fungus can easily contaminate clean harvests if storage conditions are not strictly controlled.

Effective management strategies center on moisture control and the maintenance of hygienic conditions in storage units. Drying grain to appropriate moisture levels immediately after harvest is the most critical step in prevention. Furthermore, the application of targeted chemical seed treatments is essential to protect against potential contamination during the sowing and seedling stages.

• Maintaining grain moisture below 13% for long-term storage.
• Regular monitoring of temperature levels in silos.
• Use of certified fungicide seed treatments.
• Thorough cleaning of storage facilities post-season.