Control methods of tobacco mosaic disease

Tobacco mosaic disease is common in all tobacco areas in the world, and it occurs in both northern and southern tobacco areas in China, especially in southern tobacco areas. from seedling stage to harvest period, the incidence of tobacco mosaic disease in the field is generally 520%, and in individual fields can be as high as 90% 100%. The loss of early disease can reach 50%, or even lose harvest. Let's take a look at the prevention and control methods of tobacco mosaic disease.

Harmful symptoms

After the tobacco plant was infected, the tissues of lateral veins and branch veins of young leaves were translucent, and the mesophyll tissues on both sides of leaf veins were light green. The virus proliferated massively in the leaf tissue, resulting in the enlargement or increase of some mesophyll cells, resulting in uneven leaf thickness, yellow and green color and mosaic shape. The degree of mottling of the posterior flower leaves increased, and there were large dark brown necrotic spots, especially the middle and lower old leaves, and the seriously diseased leaves were wrinkled, deformed and twisted. The plants with early disease had shortened internodes, seriously dwarfed, grew slowly, could not blossom and bear fruit normally and were easy to fall off. The shade fruit that can develop is small and wrinkled, the number of seeds is small and small, and most of them can not germinate.

Occurrence condition

Tobacco common mosaic disease mainly occurs from seedling bed stage to field budding stage. Temperature and light affect the disease spread and epidemic speed to a great extent. High temperature and strong light can shorten the incubation period, continuous cropping or interplanting with Solanaceae crops can increase the source of toxin, incidence and disease degree increase significantly, unsanitary cultivation is an important cause of epidemic, touching between diseased and healthy plants, applying immature organic fertilizer. Cultivation of soil with virus can aggravate virus transmission, soil hardening, dry climate, and serious disease in the land with severe nematode damage in the field.

Prevention and cure method

1. Select disease-tolerant varieties with strong growth, fast development and adapting to local conditions, such as Liao 44, 6315, Guanghuang 54,176, Nc89, G80, 8611, etc., pay attention to the breeding of high resistance varieties. Rotation should be carried out without intercropping or intercropping with Solanaceae plants, but should be rotated with Gramineae crops for 2 to 3 years. When mosaic disease occurs, it is necessary to apply available fertilizer, cultivate soil and water in time, promote the opening of straw and slice, and reduce the disease.

2. The seedbed should select plots that have not planted tobacco and Solanaceae plants for more than 2 years, far away from vegetable fields, select seeds collected from disease-free fields, or soak the seeds with 0.1% silver nitrate or 0.1% 0.2% zinc sulfate and 0.1% trisodium phosphate solution for 10 minutes to remove the virus on the seed surface and rinse the seeds repeatedly after soaking. Wash the seedlings with soap before fixing the seedlings, manage the seedlings first, and pull out the diseased plants in time.

3. To strengthen the field management, it is strictly forbidden to move the diseased tobacco seedlings into the field, and the sequence management of healthy plants before diseased plants should be carried out first. It is not suitable to smoke in the process of operation, and it is not suitable to walk and touch repeatedly in the tobacco field. Applying sufficient nitrogen, phosphorus and potassium fertilizer and spraying many kinds of trace element fertilizer in time to improve the disease resistance of the plant. After transplanting, the seedlings were properly refined and critical water was poured at the end of the cluster to promote plant growth.

4. At the initial stage of the disease, 6000-fold solution of 2% aminooligosaccharin, or high-tech 32% bromo-morpholine guanidine, 1.5% Zhishiling emulsion or 10% virus king wettable powder, 300 times and 500 times of Rib% Huayening wettable powder were sprayed to prevent and alleviate the damage of the virus.

5. Aphids play a decisive role in the transmission of tobacco common mosaic disease, and generally propagate 15-17 generations in the way of parthenogenetic viviparity in tobacco. Therefore, aphids should be sprayed on the surrounding peach orchards, vegetables and weeds every year from March to April to kill the tobacco aphids that have been or are hatching and reviving, so as to achieve the purpose of prevention.