Eurotium rubrum

Pathogen and disease type. Eurotium rubrum is a xerophilic mold fungus and the teleomorphic (sexual) state of Aspergillus ruber. It is recognized as a significant post-harvest pathogen that thrives in low-water environments, making it a persistent and difficult-to-control contaminant in agricultural storage facilities.

Affected crops. This fungus primarily attacks stored seeds of cereals, legumes, and oilseeds. It also frequently contaminates processed plant materials such as flour, animal feed, dried fruits, and nuts. Any stored organic matter with sub-optimal drying or poor ventilation is a potential host for this mold species.

Symptoms and signs. The characteristic sign of Eurotium rubrum infection is the development of a reddish or rusty-brown powdery coating on the surface of the affected grains. Infested seeds typically show a dull appearance, a musty odor, and, under microscopic inspection, severe degradation of the seed coat and embryo viability, often leading to complete seed failure.

Development and pathogenicity. The fungus prefers temperatures between +10 °C and +35 °C and can grow at water activities as low as 0.70–0.75. Its primary harmful impact includes the heating of grain bulk, nutritional degradation, and the potential production of secondary metabolites. This results in significant financial losses for producers due to the total spoilage of stored commodities.

Protection and prevention. Controlling Eurotium rubrum requires strict adherence to post-harvest handling protocols to deny the fungus its required moisture:

• Drying all grain and seed stock to moisture levels below 14% prior to storage.
• Maintaining consistent ventilation to prevent moisture migration and condensation.
• Implementing rigorous sanitation programs for storage bins and handling equipment.
• Monitoring temperature fluctuations to identify potential hotspots before spoilage occurs.