Tobacco mosaic disease comprehensive prevention and control of pesticides

Tobacco mosaic disease is one of the three major diseases of tobacco. The incidence of tobacco in the early stage of seedlings or in the field has seriously affected the yield of tobacco. After the topping, the incidence has little effect on the yield, but it has a great impact on the quality. The disease is caused by a variety of viruses, mainly in the production of common mosaic disease and cucumber mosaic disease. When controlling, it is necessary to pay attention to the two-pronged approach of pesticide control and comprehensive prevention.
First, the symptoms 1. Common mosaic disease: Infected by virus, the young leaves begin to develop, and the color of the mesophyll along the veins turns yellow and the veins appear. Then the dark or light-colored parts gradually enlarge to form yellow-green mottled (flowers); in severe cases, the leaves become thick and uneven, forming bubble spots, the leaf edges curl toward the back, the leaves are wrinkled and twisted, deformed, and there are nicks Or ribbon. Early onset, the plant is seriously dwarfed, the internodes are shortened, no hair is grown, and leaves are not opened.
2. Cucumber mosaic disease: Infected by virus, the veins are transparent at the beginning of the disease, and the leaves are changed later. The leaves are narrowed and twisted, and the surface hairs fall off and lose luster. Some diseased leaf leaves often curl upwards, some appear yellow-green or dark green vesicles, some have brown necrosis of the lateral veins of the leaves, or dark brown lightning-like necrosis along the veins. The plants are obviously dwarfed and the roots are stunted, and the leaves of the dead are often "flower spots".
Second, the incidence of law 1. Common mosaic disease: According to the pesticide network , the virus can survive in the disease for a long time. Mainly mixed with soil, fertilizer, seeds and other sick bodies as well as some poisonous hosts such as tomatoes, canola, mustard or perennial weeds. It is transmitted by contact with juice, that is, it invades the host from the micro-wound of mechanical friction, and spreads through human, wind, insect and other media: from the seedbed to the prolonged period, it is susceptible to disease, and the resistance is enhanced after topping. The temperature of 18-30 ° C is most suitable for the onset. Near the villages and towns, roasting tobacco houses, acquisition sites, roadsides, vegetable fields and former tobacco fields and vegetables, the incidence of tobacco fields is heavier; after transplanting, the management of fertilizer and water is not good, the soil is thin, compact, sticky, poorly drained, and the growth of tobacco plants Poor field is seriously ill.
2. Cucumber mosaic disease: The virus cannot survive in dry tobacco under natural conditions. It mainly winters in winter vegetables, vegetable plants or perennial weeds. In the spring of the following year, it was mainly caused by the spread of haze. Therefore, the more weeds, the tobacco fields close to cucumbers, tomatoes and other vegetable fields, the high temperature and drought, and the large amount of aphids, the incidence is serious. Too much nitrogen is applied, and when the soil is poor, compact, and sticky, the incidence is also serious.
Third, prevention and control technology 1. Choose high-yield and disease-resistant varieties. Such as Kirk 176, K394, g346, K326 and NC series.
2. The seedbed is preferred and the rotation is reasonable. The seedbed should choose a field with good soil fertility, shelter from the wind, easy irrigation and drainage, and the former as a rice and away from the vegetable plot, the baking room and the drying shed. At the same time, Daejeon should implement the rotation of rice and water, which can greatly reduce the pathogens and reduce the harm.
3. Soil disinfection. Combined with winter turning and whitening. The seedbed can generally be incinerated and disinfected. The critically ill area can be fumigated with methyl bromide, and the nutrient soil should be selected. Daejeon can be disinfected with 60 kg of lime. It can eliminate pathogens, pests and weeds in the soil.
4. Strengthen cultivation management. Early seeding early planting, single ridge sorghum cultivation, cultivation of disease-free and strong seedlings; rational fertilization, scientific management of water, promote early rapid growth, and enhance the resistance of plant spiders.
5. Clean the garden, timely weeding and weeding. Timely clearing the foot, rotten leaves, diseased leaves, leaflets, etc. in the field, eradicating the weeds around the garden and burning them intensively; prohibiting the use of farmhouse fertilizers with toxic tobacco residue, smoke debris, tobacco ash, and rubbish soil in front of the house Used as nutrient soil or tobacco field fertilizer. At the same time, pay attention to the field operation, in the order of the first strain of the plant, and avoid mechanical damage, reducing the spread of human contact. After the tobacco leaves are harvested, all the tobacco fields should be thoroughly cleared, and the tobacco stalks and diseased plant residues should be burned intensively to remove the pathogens.
6. Promptly control aphids and cut off the source of poison. It can be sprayed with 40% omethoate 1000-1500 times liquid or 20% speed killing 3000--4000 times liquid and 50% anti-Poly 800-1500 times liquid. The temperature is high, the weather is dry, and the number of locusts is controlled by continuous spraying. At the same time, it can also be promoted by silver mulching cultivation. The silver film has obvious effects on smashing, which is beneficial to avoid the one-month susceptibility stage after transplanting.
7. China Pesticide Network reminds everyone that prevention and treatment should pay attention to spraying once in the big cross period, seedling stage, field re-emergence period and group period of the seedbed. The medicament may be sprayed with 20% Viral B500 solution or 1.5% phytopathogenic 800-1200 times solution, 1% virus agonist, and 83-1 reinforced agent 100 times solution.