Sclerotinia sclerotiorum is also called cabbage soft rot, or cabbage white rot. It is a fungal disease, usually caused by the parasitism of Sclerotinia sclerotiorum. Sclerotinia sclerotiorum may occur in northern and southern China where cabbage is grown. This disease will not only harm Chinese cabbage, but also vegetables such as kidney beans, peppers, lettuce, cucumbers, spinach, broad beans, carrots and potatoes. Sclerotinia sclerotiorum can occur in seedling stage, core stage and planting stage. When planting Chinese cabbage, low terrain, poor drainage, humid vegetable environment and biased application of nitrogen fertilizer are all conducive to the occurrence of Sclerotinia sclerotiorum, affecting the growth of Chinese cabbage and reducing its yield and quality. Therefore, when planting Chinese cabbage, corresponding measures should be taken to reduce the occurrence of Sclerotinia sclerotiorum, thus improving its yield and quality.

Sclerotinia sclerotiorum can harm lettuce, celery, eggplant, pepper, cucumber, leek, spinach, cabbage and other vegetables except Chinese cabbage, especially in protected cultivation. The middle and lower reaches of the Yangtze River are mainly from February to June in spring and autumn 10- 12. Vegetables are most likely to get sick in the middle and late growth period. In early spring, the temperature is low, rainy or rainy, and the disease is serious in rainy years during plum rain; Late autumn is characterized by low temperature, early cold current, rainy and foggy. When plants get sick, waterlogging spots first appear, and then become white spots, which will seriously lead to plant rot.

First, clear the ditch system in time, reduce the humidity in the field, and create an environment conducive to crop growth but not conducive to the breeding and spread of germs;

Second, remove diseased plants from vegetable planting areas and destroy them to eliminate the source of germs; Move diseased leaves, yellow leaves and old leaves close to the ground to avoid spreading diseases by plants themselves;

3. Chemical control: 25% prochloraz 800- 1000 times emulsifiable concentrate or 40% flusilazole 8000 times emulsifiable concentrate and 800 times new high-fat film liquid can be mixed and sprayed evenly, and caught in the sun and dried (after dew is completely dried).

1. Damage symptoms of Chinese cabbage at seedling stage: When Chinese cabbage is planted, if it is damaged by Sclerotinia sclerotiorum, it usually occurs on the stems of Miao Di. At this time, waterlogging will appear on the stems of seedlings. When the pathogen spreads in the seedling stem, the seedling stem will rot or the seedling will collapse, thus affecting the growth of Chinese cabbage seedlings.

2. Harmful symptoms of cabbage: After cabbage is harmed by Sclerotinia sclerotiorum, it usually appears on the side of cabbage and near the stem base. At this time, if you are injured, there will be water stains on the side of the dish or the base of the stem, and there will be some pits. When the disease first appeared, the color of spots was usually light brown. When the pathogen spreads, the color of the spots will turn brown or gray.

3. Harmful symptoms of cabbage in seed stage: some of the cabbage planted is used for seed reservation. When Chinese cabbage plants are in the seed stage, such as Sclerotinia sclerotiorum, the roots, petioles and pods of the plants will generally appear yellow-brown spots in the early stage of the disease. When the pathogen spreads, the color on the diseased spot will gradually turn gray, which will cause serious damage to the diseased plant and rot, and then make the plant collapse from the diseased site.

When the pedicels of Chinese cabbage plants are invaded by pathogenic bacteria, white hyphae will grow on the invaded parts, leading to water rot. Generally speaking, this will affect the normal absorption of nutrients and water by pods, resulting in pods not bearing normal fruits. When the vegetable field is wet, white villi will grow on the diseased parts invaded by Sclerotinia sclerotiorum, and black-brown sclerotia will appear like mouse feces.