Green mould

Penicillium digitatum

Penicillium digitatum is a fungus that is a major post-harvest pathogen affecting citrus fruits, particularly oranges and lemons. It is commonly known as green mold due to the characteristic green spore-producing structures that develop on infected fruit. Here's an informative description of Penicillium digitatum, including its appearance, identification, and management:

1. Symptoms:

  • Surface Lesions: Penicillium digitatum causes green mold on citrus fruits, resulting in circular, depressed lesions on the fruit's surface.
  • Spore Production: The lesions are often covered with a green powdery mass, representing the spore-producing structures of the fungus.

2. Disease Cycle:

  • Infection: The fungus enters the fruit through wounds, bruises, or natural openings.
  • Spore Germination: Upon infection, the fungus produces conidia (asexual spores) that germinate and penetrate the fruit's peel.
  • Lesion Development: Lesions become visible as the fungus grows within the fruit, and green spore masses develop on the surface.
  • Spread: Spores are easily dispersed by wind, water, or contact, leading to the contamination of healthy fruits.

3. Identification:

  • Green Spore Mass: The characteristic green powdery mass on the fruit's surface is a key identifier.
  • Lesion Appearance: Circular lesions with depressed centers and a greenish hue are indicative of Penicillium digitatum infection.

4. Management:

  • Preventive Measures: Implementing good post-harvest practices, including careful handling to minimize wounds and bruises, is crucial.
  • Fungicide Applications: Application of post-harvest fungicides, especially those effective against Penicillium species, can help control green mold.
  • Temperature and Humidity Control: Maintaining cool temperatures during storage and transportation and controlling humidity can inhibit the growth and spread of the fungus.
  • Sanitation: Proper sanitation practices in packinghouses and storage facilities, including the removal of infected fruits, help reduce inoculum.

5. Importance:

  • Economic Impact: Green mold caused by Penicillium digitatum can lead to significant economic losses due to the deterioration of fruit quality during storage and transportation.
  • Global Distribution: The pathogen is prevalent in citrus-producing regions worldwide.