Barese Swiss Chard Seeds

BR - Black Rot

Scientific Name: Xanthomonas campestris

Type: Bacterium

Black Rot is a disease that affects the growth of arugula, broccoli, Brussels sprouts, cabbage, cauliflower, collards, kale, kohlrabi, mustard, radishes, rutabaga, Swiss chard, tomatoes, turnips, and watercress. It survives in warm wet weather and affects cabbage throughout the United States. It is spread from one field to another field by water and wind. The bacteria can infect seeds and young seedlings. Young plants infected will turn yellow, drop lower leaves, and may die. Once the plant is infected there is no rescue treatment since the infection is systemic. Symptoms include the yellowing of the leaves in v-shape or wedge-shaped patches and blackening of the internal vein. Usually only a few of the outer leaves are affected. Since the disease is spread by water, anything that can be done to reduce leaf wetness will help reduce the spread of the disease. Water the plants in the morning, instead of the watering in the afternoon or night, so the leaves have time to dry before sunset. Increase space between the plants to maximize air flow and drying of the leaves. The disease is favorable when temperatures are 75-95 F and rain, heavy fogs, and dew are present. The bacteria does not spread when temperatures are below 50 F or during dry weather. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in the soil for two years. Treating the infected area with fungicides can help manage the disease. The primary source of bacteria of black rot is infested seeds and in infested transplants. The best option is to use disease resistant varieties, disease-free seeds, and disease-free transplants.