Anthracnose of Lupins

Causal Agent: Anthracnose in lupins is primarily caused by various species of fungi belonging to the genus Colletotrichum. The specific species involved may vary, with Colletotrichum lupini being one of the common culprits.

Symptoms:

1. Leaf Lesions:

   • Circular Lesions: Anthracnose lesions on lupin leaves are typically circular and may vary in size.
   • Dark Centers: Lesions often have dark brown to black centers.
   • Reddish Margins: The margins of the lesions may appear reddish.

2. Stem Lesions:

   • Lesions on Stems: Stems may develop lesions, affecting the overall health of the plant.

3. Pod Lesions:

   • Lesions on Pods: Anthracnose can cause sunken lesions on lupin pods.
   • Conidia Formation: The fungus produces conidia (asexual spores) within the lesions.

4. Seedborne Infection:

   • Infected Seeds: Anthracnose can lead to the development of infected seeds.
   • Reduced Seed Quality: Infected seeds may exhibit reduced germination and seedling vigor.

Identification:

1. Circular Lesions: Circular lesions with dark centers on leaves, stems, and pods.
2. Reddish Margins: Reddish margins around the lesions, particularly on leaves.

Conditions Favoring Disease:

1. Warm and Humid Conditions: Anthracnose thrives in warm and humid environments.
2. Rain or Irrigation: Moisture on leaves and pods from rain or irrigation facilitates spore dispersal and infection.

Management:

1. Resistant Varieties:

   • Plant Resistant Cultivars: Choose lupin varieties that show resistance or tolerance to Colletotrichum species causing anthracnose.

2. Cultural Practices:

   • Crop Rotation: Rotate lupin crops with non-host crops to reduce inoculum.
   • Sanitation: Remove and destroy infected plant material, including crop residues.
   • Proper Spacing: Ensure adequate spacing between plants for good air circulation.

3. Fungicides:

   • Protective Fungicides: Application of fungicides may be considered, especially during periods conducive to disease development.

4. Seed Treatment:

   • Seed Treatment: Treat lupin seeds with fungicides to reduce the potential for seedborne infection.

Note: Integrated disease management, combining cultural practices, resistant varieties, and, if necessary, fungicides, is often the most effective approach.