The latest control methods of tobacco mosaic disease

Tobacco mosaic disease is widespread in all tobacco areas of the world, and occurs in both northern and southern tobacco areas of China, especially in southern tobacco areas. The incidence of disease in field plants can be as high as 5~20% from seedling stage to harvest stage. The loss of early disease can reach 50~70%, even loss of harvest. Let's take a look at the prevention and control methods of tobacco mosaic disease together.

hazard symptom

After tobacco plant infected, the lateral veins and collateral veins of young leaves were translucent, and the mesophyll tissues on both sides of veins gradually became light green. Viruses proliferate in large quantities in leaf tissues, making some mesophyll cells enlarge or increase, resulting in uneven leaf thickness, yellow and green color, and mosaic. After mottled degree increased, and a large area of dark brown necrotic spots, especially in the middle and lower parts of the old leaves, seriously affected leaves shrinkage, deformity, distortion. Early diseased plants have shortened internodes, serious dwarfing, slow growth, abnormal flowering and fruiting, and easy to drop off. The shade fruits that can develop are small and shriveled, the seed quantity is few and small, and most of them cannot germinate.

generation condition

temperature and light greatly affected the spread and epidemic speed of the disease. High temperature and strong light could shorten incubation period. Continuous cropping or interplanting with Solanaceae crops increased virus source, incidence and degree of disease obviously. Unsanitary cultivation was an important cause of epidemic. Touching between diseased and healthy plants, applying undecomposed organic fertilizer and cultivating soil with virus could aggravate virus infection. Soil hardening, dry climate, Field nematodes seriously damaged the plots of heavy disease.

control methods

1. Select resistant varieties such as Liao44, 6315, Guanghuang54, 176, Nc89, G80, 8611, which have strong growth potential, rapid development speed and adapt to local conditions, and pay attention to the breeding of high resistant varieties. Rotation should be carried out, not intercropping with solanaceae plants, but with gramineous crops for 2~3 years. In case of mosaic disease, quick-acting fertilizer shall be applied timely, soil cultivation and watering shall be carried out, straw opening shall be promoted, and disease shall be alleviated.

2, seedbed should be selected more than 2 years without planting tobacco and solanaceae plants, away from the vegetable field plot, select from the disease-free field disease-free plants harvested seeds, or with 0.1% silver nitrate or 0.1~0.2% zinc sulfate, 0.1% trisodium phosphate solution soaking for 10 minutes, remove the virus on the seed surface, after soaking to wash repeatedly. Thinning seedlings, fixed seedlings before washing hands with soap, operation of the first good management seedlings, found that the disease plant removed in time.

3. Strengthen field management. It is strictly prohibited to move diseased tobacco seedlings into the field. Healthy plants should be managed first and then diseased plants. Smoking should not be allowed during operation. Repeated walking and touching in tobacco fields should not be allowed. Apply enough nitrogen, phosphorus, potassium fertilizer, timely spray a variety of trace element fertilizer, improve plant disease resistance. After transplanting, the seedlings should be tempered properly, and critical water should be poured at the end of the cluster to promote the growth of the plants.

4. At the early stage of disease, spraying with 2% amino oligosaccharide 6000 times solution, or Gao Ke 32% nucleoside bromomorpholine 800 times solution, or 1.5% Zhibingling emulsion 1000 times solution, or 10% virus king WP 600 times solution, Ri % Huaxianning WP 300~500 times solution can prevent and alleviate virus damage.

5. Aphids play a decisive role in the spread of tobacco mosaic disease. They generally reproduce in the form of parthenogenesis for 15~17 generations. Therefore, in the control of aphids, concentrated spraying should be done to the surrounding orchards, vegetables and weeds in March ~ April every year to kill the aphids that have hatched or are recovering, so as to achieve the purpose of prevention.