Lichtheimia ramosa

Lichtheimia ramosa is a fungal species belonging to the order Mucorales. Primarily known as an opportunistic pathogen in clinical settings, it also acts as a significant saprotroph and potential plant pathogen. It is recognized as a cause of post-harvest decay in various agricultural commodities, particularly affecting fruits, vegetables, and stored grain products under conditions of high humidity.

The host range of this fungus is extensive, covering various agricultural crops including legumes, cereals, and succulent vegetable tissues. The pathogen typically enters plant tissues through harvesting injuries, insect damage, or cracks resulting from physiological stress, rapidly utilizing available carbohydrates for its aggressive mycelial growth.

Symptoms of Lichtheimia ramosa infection are characterized by a rapidly expanding, white-to-greyish fluffy mycelium. As the fungus matures and produces sporangia, the colony often shifts to a darker, brownish-grey color. The underlying plant tissues exhibit progressive softening, liquefaction, and significant loss of structural integrity, often accompanied by a distinct fermented odor.

Development and spread of the pathogen are highly dependent on environmental factors. Lichtheimia ramosa thrives in warm environments, with optimal growth occurring between 25°C and 35°C, coupled with high relative humidity. Poor aeration in warehouses, ineffective temperature control, and high moisture content within storage bins create an ideal environment for rapid colonization and secondary spread of the fungal spores.

Management strategies focus on sanitation and post-harvest handling practices to minimize the risk of infection:

• Implementing strict temperature and humidity control in storage facilities.
• Minimizing physical injuries to crops during harvesting and transit to reduce infection points.
• Regular sanitation of storage surfaces using registered antifungal agents.
• Ensuring proper crop drying before storage to reduce moisture levels below the threshold required for fungal germination.