Anthracnose

Causal Agent: Colletotrichum acutatum is a fungal pathogen that causes anthracnose, a plant disease affecting a wide range of hosts, including various fruits, vegetables, and ornamental plants.

Symptoms:

1. Lesions:

   • Circular Lesions: Anthracnose lesions are typically circular and may start small.
   • Expanding Lesions: Lesions can rapidly expand in size, covering larger areas of the plant.
   • Sunken Centers: As lesions enlarge, they often develop sunken centers.

2. Lesion Color:

   • Initial Lesions: Lesions may begin as water-soaked and turn tan or light brown.
   • Mature Lesions: Older lesions often have a dark brown to black color.

3. Fruit Symptoms:

   • Fruit Lesions: On fruits, anthracnose can cause dark, sunken spots, making them unmarketable.
   • Rotting: Infected fruits may eventually rot.

4. Spore Production:

   • Conidia: The fungus produces conidia (asexual spores) in structures called acervuli within the lesions.

Identification:

1. Circular Lesions: Small to large circular lesions with a sunken appearance.
2. Darkening: Lesions often exhibit darkening as they mature.

Conditions Favoring Disease:

1. Warm and Humid Conditions: Anthracnose thrives in warm and humid environments, and disease incidence is higher under such conditions.
2. Rain or Irrigation: Moisture on leaves and fruits from rain or irrigation facilitates spore dispersal and infection.

Management:

1. Fungicides:

   • Protective Fungicides: Regular application of fungicides, especially during periods conducive to disease development.
   • Cultural Practices: Properly time fungicide applications based on the plant's growth stage and weather conditions.

2. Cultural Practices:

   • Sanitation: Remove and destroy infected plant material to reduce inoculum.
   • Pruning: Prune and thin plants to improve air circulation.
   • Avoid Overhead Irrigation: Minimize prolonged leaf wetness by using drip or furrow irrigation.

3. Resistant Varieties:

   • Plant Resistant Cultivars: Consider planting cultivars that show resistance or tolerance to anthracnose.

4. Post-Harvest Practices:

   • Proper Storage: If applicable, store harvested fruits in cool and dry conditions to prevent post-harvest anthracnose development.

Note: Integrated disease management, combining chemical control with cultural practices, is often the most effective approach.