Rhizomucor pusillus

Rhizomucor pusillus is a thermophilic fungus belonging to the Zygomycetes class, acting as a major causative agent of various types of mold. In agronomy, this pathogen is recognized as a serious threat that leads to the spoilage of seeds, fruits, and vegetable crops during storage, as well as the development of rots in greenhouse soils.

This fungus affects a wide range of agricultural crops, including cereal seeds, vegetable fruits such as tomatoes and cucumbers, and potato tubers. Crops are especially susceptible when stored in high-humidity conditions or when they sustain mechanical tissue damage, which provides an entry point for the pathogen.

The primary symptoms of infection include the appearance of dense, cotton-like mycelium that is gray or grayish-brown in color on the surface of the affected plant part. As the disease progresses, the plant tissues become soft, watery, and rapidly lose their marketability, often emitting a distinct odor typical of mucoraceous fungi.

The development of Rhizomucor pusillus is favored by high temperatures (with an optimum range of 35–45°C) and high ambient or substrate humidity. The fungus is highly resilient to adverse environmental factors and can survive for long periods in the soil or on plant debris as resting spores.

The economic impact of the pathogen is significant, often resulting in total loss of harvested products and reduced seed germination rates. Effective control and prevention include the following strategies:

• Seed treatment with fungicides prior to planting.
• Strict maintenance of temperature and humidity in storage facilities.
• Disinfection of storage crates and warehouse premises.
• Timely removal and destruction of crop residues.