Chinese cabbage disease prevention

The main diseases of Chinese cabbage include downy mildew, viral disease, soft rot, black rot and dry heart disease. The first three diseases are referred to as the three major diseases of cabbage; the main pests are whitefly, aphids, cabbage caterpillars, beet armyworms. And Plutella xylostella, etc., after the occurrence of these pests and diseases, affects both the quality of cabbage and the yield of cabbage.

 

First, the disease

 

　　 1. Downy mildew: It can occur from the seedling stage to the core stage, mainly affecting the leaves of Chinese cabbage. It begins with the onset of the lower leaves, and produces water-soaked, pale yellow polygonal lesions on the leaves, which gradually expand and change. It is yellowish brown. When it is severe, the leaves are dry and cannot be eaten. The severity of the disease is closely related to climate, variety and cultivation techniques. The rainfall in autumn is relatively high, and the relative humidity is higher than 70 %, which is conducive to the occurrence of downy mildew. The sowing is too early, the density is too large, the nitrogen fertilizer is applied, and the drainage in the field is bad.

 

Prevention:

 

(1) agricultural control: First, close planting, the early maturing variety grown per acre 2500-3000 strain, strain maturing varieties acre Planting 2000-2400: Second balanced fertilizer, fertilizer topdressing multi-element, to avoid partial nitrogen; Third, timely drainage after the rain to prevent water accumulation in the field.

 

( 2 ) Chemical control, 40 % ethylphosphorus aluminum 800 times solution, 58 % metalaxyl manganese zinc 500 times liquid or 1.5 % frost plague 1000 times liquid foliar spray can be used at the beginning of the disease; the disease can be used in frost or 72 % DuPont Kelu 800 times liquid leaf spray, once a week, even spray 2-3 times.

 

　　 2 , viral disease: Symptoms are divided into two types, one is the mosaic type: the leaves produce uneven green uneven mottled or mosaic; the second is the shrinkage type: the heart leaves are shrunken deformed, hard and brittle.

 

The occurrence of the disease is related to climate, management and other factors. After sowing, the cabbage is exposed to high temperature and drought, the root growth and development is inhibited, and the disease resistance is reduced. In addition, the high temperature and drought are beneficial to the occurrence of aphids, the probability of spreading the virus is high, and the virus disease is serious. In addition, the management is extensive, and there is a lack of water and fat.

 

Control measures: Cabbage virus disease is transmitted by aphids, so it is very important to control aphids. It can be sprayed with 10 % imidacloprid 2000 times, once every 7-10 days, and even 2-3 times. After the cabbage is infected, spray 1.5 % of the planting disease No. 2 800 times liquid or virus nemesis, Kangrun No. 1 1000 times liquid leaf spray, once a week, and even prevent 2-3 times.

 

　　 3 , soft rot: from the cabbage rosette period to the core period, there are often two types, one is wilting type: cabbage in the sunny day at noon, wilting, sooner or later, after a few days, the whole plant died ; the second is soft rot Type: The petiole petiole or leaf ball of the cabbage is sticky and slippery, and emits an odor.

 

The severity of the disease is related to climate, sputum, sowing date, etc. If there is much rainfall, the surface water is conducive to the disease, and the planting is too early, and the continuous crops are seriously affected.

 

Control measures: ( 1 ) Agricultural control: avoid continuous cropping, prevent land area water, find disease plants in time to remove, bring out field destruction,

 

Prevent spread. ( 2 ) Chemical control: It can be sprayed alternately with 72 % agricultural streptomycin 3000 times solution, 3 % kebukang 1000 times solution, 20 % lonke bacteria 500 times solution, once a week, even spray 2-3 times.

 

　　 4 , dry heart disease: generally occurs in the rosette period of cabbage, the young leaves show dry edges, the symptoms are obvious during the ball-forming period, the upper part of the leaves gradually dry and yellow, the leaf flesh is dry paper, the veins are yellowish brown to dark black. The location of the disease is mainly in the middle of the leaf.

 

The disease is a physiological disease caused mainly by the lack of calcium and manganese nutrients.

 

Prevention:

 

( 1 ) Add organic fertilizer.

 

( 2 ) Chemical control: In the seedling stage of cabbage, 0.7 % manganese sulfate plus green Fenwei 3 spray before the rosette stage or the core period .

 

Source: China Agricultural Promotion Network

 

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