ring spot disease is one of the main diseases of cauliflower, which mainly infects leaves, resulting in yield reduction and loss of cauliflower. Ring spot disease mainly harms leaves, with nearly round to round grayish white in the middle of leaves and brown to purple-brown spots on the edges. There are often yellow halo around the spots, and small black spots appear on the spots in the late stage of the disease. Clean up the accumulated water in the field in time after the rain, strengthen the management of fertilizer and water, clean up the sick and disabled bodies in the field in time after harvesting and destroy them outside the field. Also known as ringspot disease. Broccoli and purple cabbage are mainly harmful to leaves, with gray-white circular spots, the size is 5 ~ 15 mm, the edge is not obvious, there are yellow-green halos around, and there are black spots in the later stage, that is, pathogen conidia. The pathogen of cauliflower brown spot overwinters by mycelium or conidia, and also overwinters on the surface of plants and seeds, and becomes the source of infection at the beginning of the second year. Pathogenic conidia spread through airflow, and then infect and spread diseases.

The disease is a bacterial disease, which is caused by the invasion of Xanthomonas campestris subspecies, and can occur in the seedling stage, mature stage, nodulation stage and seed retention stage of cauliflower. Pathogens can overwinter in seeds or stay in the soil where the disease remains undecomposed, and invade from wounds or leaf margin water holes through seeds, insects, rain, man-made, and then enter vascular tissue, expanding to form systematic infection. Wounds caused by field work or insect pests are more conducive to the invasion of germs. Sterilization with disease-free seeds or seeds, rotation, early detection of diseased plants and removal of diseased leaves. At the initial stage of the disease, 5% prometryne wettable powder 15 times, 8% spray wettable powder 6 times, or 8% Xinwansheng wettable powder 6 times can be used for prevention and control, spraying once every 7 days for 2 ~ 3 times continuously.

select disease-resistant varieties, rotate them reasonably, and pull out diseased plants in time. At seedling stage, aphids should be prevented in time, and water management should be strengthened to avoid plant diseases caused by high temperature and high humidity. Amino oligosaccharides and bacterial toxins combined with amino acid biostimulants sprayed on leaves can also be used for prevention. Strengthen field management, timely release air, adjust temperature and dehumidify at seedling stage, timely interplant seedlings and reasonable close planting. Dust method and smoke method are the first choice in protected areas, and spray control can also be carried out in dry and sunny weather. Pay attention to the rotation and reasonable collocation of drugs.