Black spot disease in cabbage, also known as Alternaria leaf spot, is a fungal disease caused by the fungus Alternaria brassicicola. It is a common and destructive disease of cabbage and other cole crops, such as broccoli, cauliflower, kale, and Brussels sprouts. The amount of leaf area affected by the disease plays a crucial role. Minor infections might only reduce marketability, while heavy infections can significantly impact head size and weight. Earlier infections, particularly during seedling stage, can be more detrimental than later ones closer to harvest.
- Type of Infestation: Fungal Disease
- Common Name: Black Spot
- Causal Organism: Alternaria sp.
- Affected Parts Of the plant: Leaf, Stem, Seed
Environmental favorable factors for pests/Diseases:
- Warm, humid weather (temperatures between 60 and 90°F)
- Frequent rain or overhead watering
- Poor air circulation in the crop canopy
- Injury to the leaves from insects or other pests
Symptoms of Pest/Disease:
- Small, brown to black circular spots on the leaves, typically starting on older leaves near the bottom of the plant
- Spots may have concentric rings, giving them a target-like appearance
- As the spots enlarge, they may merge together, causing the leaves to yellow and die
- In severe cases, the disease can affect the head of the cabbage, making it unmarketable
Measures to control Pests/Diseases:
| Products | Technical Names | Dosages |
| DR . Blight | Metalaxyl-M 3.3% + Chlorothalonil 33.1% SC | 300-400 ml/acre |
| k-zeb | Mancozeb 75% WP | 500gmsl per Acre |
| striker | Pseudomonas Fluorescens Bio Fungicide Powder | 5 kg per acre |
