Basidiobolus ranarum

Basidiobolus ranarum is a zygomycete fungus primarily recognized for its saprophytic existence in soil and organic matter. While commonly studied in microbiology, in the agricultural context, it acts as an opportunistic colonizer of plant tissues, particularly when environmental conditions facilitate the breakdown of plant cell walls.

As a member of the order Entomophthorales, this organism possesses a high capability for degrading cellulose and other complex organic compounds. Under specific conditions, it can become an opportunistic pathogen, affecting seedlings and plants that are already stressed by environmental factors or mechanical injury to their roots and stems.

Symptoms typically manifest as soft rot or dark, necrotic lesions on the basal parts of the plant. Infected plants may exhibit stunted growth, wilting, or death of the lower foliage. The presence of the fungus is often confirmed by the visual appearance of mycelial growth on damaged surfaces in high-humidity environments.

Development and dissemination are favored by high humidity (often exceeding 80%) and temperatures ranging from 20°C to 28°C. In greenhouses, poor air circulation and water-logged substrates create an ideal environment for the fungus to multiply and spread via spores through water splashes or direct contact with contaminated soil particles.

Effective management and protection strategies include:

• Maintaining optimal soil moisture and ensuring proper drainage.
• Improving greenhouse ventilation to reduce relative humidity.
• Removing infected plant debris to minimize the accumulation of inoculum.
• Applying fungicides when environmental conditions are conducive to fungal outbreaks to prevent economic losses.