The pathogenic bacteria of cucumber scab are overwintering with mycelium, diseased stems, leaves, tendrils, and other diseased bodies in the field or in the soil or on racks and greenhouses attached to greenhouses, and become the primary source of infestation the following year. Germs can also be conidially attached to the seed, or latent in the seed coat to winter. The sowing of diseased seeds is the main source of transmission for disease-free areas, and germs can directly infect seedlings. The conidia produced in the soil after the winter is also the primary infestation source, and is transmitted by airflow, agricultural operations, etc.