Anthracnose of Brassicas

C. gloeosporioides spores

Initial symptoms include irregular round spots on leaves and stems, which turn to greyish-brown lesions. Lesions on stems of seedlings rapidly enlarge until they finally cause damping-off. Pink conidial masses and acervuli are frequently observed on well-developed stem lesions.
This can be avoided by liming the soil, growing a resistant variety or growing in a sterile soil/compost/sand mixture.