How to prevent and control Chinese cabbage soft rot? A full analysis of practical methods
How to prevent and control Chinese cabbage soft rot? The pathogen of Chinese cabbage soft rot is a short rod-shaped bacterium of the genus Erwinia. Under conditions of 20 degrees and high humidity, the pathogen forms colonies centered on the soil in the rhizosphere of the host plant and survives for a long time. On rainy days, with the splashing of soil particles, it invades from wounds and insect feeding marks on the lower leaves and leaf stalks of Chinese cabbage, and once it encounters a host plant, it multiplies rapidly. Next, the editor will talk about the harm and prevention and control measures of Chinese cabbage soft rot, hoping it can be of some help to everyone.
Symptoms of Chinese cabbage soft rot
The symptoms of this disease vary slightly depending on the different host crops, different parts of the plant, and different environmental conditions. However, the site of onset always starts from a wound. When generally soft and juicy tissues are affected, they first appear water-soaked and semi-transparent, then the epidermis sinks and turns brown, and the diseased tissue then rots, appearing sticky, slippery, and soft-rotted, and giving off a foul odor. When firmer, less juicy tissues are affected, they also first appear water-soaked and gradually rot, but in the end the diseased tissue shrinks and becomes dry-rot.
In the field, Chinese cabbage mostly begins to develop the disease from the early heading stage. Generally, the base of the outer leaves is affected first, and the affected area shows water-soaked, slightly yellow lesions that gradually expand, turn light yellow or yellow-brown, and rot, producing a foul odor. l—2 days after the lesions appear, the vascular bundles in the diseased area turn yellow to brown, and through the vascular bundles the disease spreads rapidly to the stem and roots, thereby causing other leaves or the whole plant to become diseased. In the early stage of the disease, the leaves wilt at noon and recover in the morning and evening. As the disease progresses, the affected outer leaves no longer recover and collapse to the ground, exposing the head, which is called "shedding of the outer leaves." At this time, because the base has already rotted, the head is very easy to knock off with a kick, and the pith at the base of the leaf stalks and the root crown is filled with gray-brown viscous material, with an overwhelming stench, which is called "rotten lump." Rot inside the head is called "sauce barrel." Some diseased plants have scorched edges on the outer leaves or rotting at the tips of the inner leaves. The rotten diseased leaves, under the condition of clear, warm, and dry weather, can quickly lose water and become like thin paper. When the disease occurs during cellar storage, it mostly starts from wounds on the outer leaves.
Prevention and control methods for Chinese cabbage soft rot
(1) Change the planting pattern by changing traditional flat-bed planting to ridge planting. The specific method is: according to the row spacing required for Chinese cabbage, form ridges on the plowed land, generally with a ridge height of 8-10 cm, and spread a layer of wheat bran or chopped wheat straw mixed with phoxim or dichlorvos pesticide in the furrows between the ridges. This can both prevent insects and prevent weeds from growing in the furrows. Later, when watering the Chinese cabbage, the amount of water should preferably be such that the water is level with the furrows.
(2) Choose disease-resistant varieties. Generally, choose tall-cylinder varieties or green hemp leaf, such as Beijing New No. 3, Jin Vegetable No. 3, Taiyuan Erqing, etc. If ball-type varieties such as Fengkang 80 must be planted, the sowing date can be appropriately postponed to 2-4 days after the Start of Autumn, or seedlings can be raised and transplanted. In this way, the heading of Chinese cabbage can avoid the period of high temperature and high humidity, greatly reducing Chinese cabbage soft rot caused by high temperature and high humidity.
(3) Choose the right crop rotation and avoid continuous cropping. Generally, the previous crop should be a plot planted with scallions, garlic, or kidney beans, and wheat stubble is even better. In this way, infection by soft rot pathogens due to continuous cropping can be avoided.
(4) Apply pesticides at the right time for prevention. After Chinese cabbage is planted, use a 3000-4000 times dilution of 72% agricultural streptomycin or 20% validamycin water-soluble powder, with each 25 g bag mixed with 50 kg of water, for pesticide prevention. In addition to spraying the whole field, the pesticide solution should also be focused on spraying the base of the Chinese cabbage roots, with about 100 g of pesticide solution per plant, so that the pesticide solution penetrates into the soil at the root of the Chinese cabbage. Spray once every 7-10 days, for 2-3 consecutive sprays. If scattered soft rot plants are found, they should be immediately pulled out and taken out of the field, quicklime should be scattered in the pits of the removed diseased plants, and the above pesticides should continue to be used for spraying treatment.
That is all for the introduction of prevention and control methods for Chinese cabbage diseases. Chinese cabbage soft rot has a great impact on the later growth of Chinese cabbage, so everyone must do a good job in preventing and controlling Chinese cabbage soft rot in a timely manner.