Penicillium rot

The causative agent of this disease is the fungus Penicillium divergens, a member of the genus Penicillium. It is a cosmopolitan organism commonly associated with the post-harvest deterioration of various crops, acting primarily as a storage pathogen.

This fungus affects a wide range of agricultural products, including fruits, vegetables, and stored grains. It typically targets produce that has sustained mechanical injuries, as the broken skin or seed coat provides an easy entry point for fungal mycelium to colonize the nutritious internal tissues.

The diagnostic signs of the infection include the formation of powdery, cushion-like colonies that are typically blue-green or grey-green in color. The infected areas exhibit soft rot, tissue maceration, and a distinct musty odor, rendering the produce completely unmarketable and often toxic if mycotoxins are produced.

The development of Penicillium divergens is highly dependent on humidity and temperature. Relative humidity levels exceeding 85% and improper cooling in storage facilities significantly accelerate the sporulation process and the spread of the pathogen between adjacent units of produce.

• Maintaining rigorous sanitation protocols in storage facilities.
• Ensuring continuous and adequate air circulation to prevent moisture accumulation.
• Strict temperature control to inhibit fungal growth rates.
• Preventing physical damage during harvesting and transportation.
• Applying preventive antifungal treatments to seed stock before planting.

The economic impact of Penicillium divergens is severe due to its rapid colonization capacity. Once the fungus establishes itself in a storage batch, it can spread exponentially, leading to total post-harvest failure if sanitary barriers are breached or ignored during the storage period.