In recent years, Bemisia tabaci has been ravaged by cotton and protected vegetables in our province, especially after B. tabaci emergence. Recently, Tomato yellow leaf curl virus disease caused by the transmission of B. tabaci was popular in tomato production areas in our province. Because Tomato yellow leaf curl virus disease is a new virus disease, farmers have no knowledge of the disease's pathogenesis and prevention and control measures, and there are more fields in the production. It is imperative to understand the ins and outs of the disease and find out the appropriate prevention and control measures to curb the spread of the disease. To this end, the reporter interviewed Zhao Tongmin, an associate researcher at the Vegetable Research Institute of the Vegetable Institute of the Provincial Academy of Agricultural Sciences.
First, what happened
It is understood that tomato is one of the major vegetable crops in our province. Its annual cultivation area is over 700,000 mu, which occupies an important position in the annual supply of vegetables. Tomato mosaic virus disease and cucumber mosaic virus disease have been the main viral diseases in tomato production. However, since September 2005, a new virus disease (tomato yellow leaf curl virus disease) has been found in Xinghua, Jiangdu, and Nanjing. Tomatoes, such as Wuxi, have emerged one after another, seriously harming tomato growth, flowering and fruit set, causing huge losses to local tomato production.
In the autumn of 2005, Tomato yellow leaf curl virus disease first appeared in the tomato production areas of Jiangdu and Wuxi, and caused devastating damage to some of the blocks in Jiangdu. Later, it gradually expanded and spread, and the damage was becoming increasingly serious. In the fall of 2007, the disease was severely occurring in tomato cultivated in sunlight greenhouse in Zhaoyang Town, Xinghua City. The field diseased plant rate was more than 80%, and the diseased plant rate was as high as 100%.
Second, the incidence of the law
Tomato yellow leaf curl virus belongs to the genus Vibrio cholerae virus, and the host is Goose velvet vine, Mandala, Pekinbean, Tomato, Gooseberry tomato, Benzinia, Heart smoke, Tobacco, Kidney bean, Lettuce and other plants. Bemisia tabaci is the main mediator of Tomato yellow leaf curl virus disease. It can be transmitted for a lifetime after being poisoned but not transmitted by eggs. Mechanical friction and seeds are not transmitted, and grafting can cause the virus to spread. The rapid increase in the number of B. tabaci insecticides and their ability to transmit viruses are the main causes of the outbreak of B. tabaci in our province and the prevalence of tomato yellow leaf curl virus disease in recent years.
After infected with the virus, the tomato plants mainly showed growth retardation or stagnation, internode shortening, plant dwarfing, small and thick leaves, hard and hard leaves, wrinkled, upward curled leaves, leaf edge to vein yellowing area, The symptoms of the upper leaves of the plants were typical, and the symptoms of the lower old leaves were not obvious; the later performance was less in fruit set, the fruit became smaller, the rate of enlargement was slow, and the fruit in the mature stage could not be normalized. Tomato plants were infected with the virus, especially before flowering, and the fruit yield and commodity value were significantly reduced.
Third, prevention and control measures
The selection of disease-resistant varieties for planting is the most fundamental measure to control tomato yellow leaf curl virus disease. Due to the phenomenon of genetic recombination of twin viruses, the frequency of virus mutation is high. Although the name of Tomato yellow leaf curl virus disease around the world is the same, the genetic composition of viruses is very different. Therefore, disease-resistant varieties of other regions were introduced into our province and planted. Not necessarily resistant to disease, need to re-edition resistant varieties. In view of the fact that there is no disease-resistant variety currently available for production, taking measures to prevent and control Bemisia tabaci is the key to controlling the spread of diseases. It can be started from sporadic occurrence of Bemisia tabaci, alternately with 25% Praxanthine WP 1000-1500 times, or 25% Aquecy Water Dispersion granules 2000-3000 times, or 2.5% Uranus EC 2,000-3000 times. Liquid, or 80% fipronil water dispersible granules such as 15000 times spray control; or within the protected area per acre with 22% dichlorvos smoke agent 200 grams of smoke, combined with irrigation or water spray to ensure the soil moisture when smoked. Through the use of 40-50 mesh insect nets to cover the cultivation, hanging in the greenhouse to kill the yellow board, timely removal of old leaves and diseased leaves, removal of weeds in the fields and greenhouses and other measures, you can reduce the mouth density of tobacco borers, cut off the route of transmission, reduce Onset.
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