Aspergillus versicolor

Taxonomic position and pathogen nature: Aspergillus versicolor belongs to the kingdom Fungi, phylum Ascomycota, genus Aspergillus. It is a microscopic filamentous fungus that primarily acts as a saprotroph but can behave as a significant opportunistic phytopathogen under environmental stress, affecting both growing plants and stored agricultural products.

Diseases and host crops: This species is a primary agent of seed and grain molding in cereals, legumes, and oilseeds during post-harvest storage. In field conditions, it is associated with root rots and seed decay. It frequently affects maize, wheat, sunflowers, and various vegetable crops in greenhouse environments, causing damage to fruits and seedlings.

Biology and life cycle: The life cycle is characterized by asexual reproduction through the formation of numerous conidia on conidiophores. These spores are disseminated via wind, water, or insect vectors. The fungus exhibits a rapid colonization rate, utilizing a robust suite of extracellular enzymes to degrade complex organic substances like starch and cellulose within the host tissue.

Conditions for development and harmfulness: Optimal conditions for growth include relative humidity above 70% and temperatures ranging from +20°C to +30°C. The major threat stems from the production of secondary metabolites, including mycotoxins like sterigmatocystin. Infected seeds lose viability, and the resulting produce becomes hazardous for food or feed due to its high toxicity.

Protection and control measures: Effective control relies on stringent moisture management during storage, ensuring grain dryness and adequate ventilation. Agronomic strategies include crop rotation, the use of certified seed dressing with broad-spectrum fungicides, and the control of field pests, as physical injuries to plants provide entry points for the pathogen to establish infection.