Sweet potato complex virus disease, or English abbreviation SPVD, is caused by the co-infection of feathery mottle virus and chlorotic dwarf virus. Its occurrence has a certain relationship with virus accumulation, and the symptoms are not obvious when the virus volume in plants is small. The long incubation period of up to 3 years has a great impact on the output of sweet potato, which generally reduces the yield of sweet potato by 50% to 90%, and even leads to an unacceptable harvest. What is more important is that there is no cure at the moment and it is a devastating disease in sweet potato production.
Symptomatic causes: Caused by leaf distortion, malformation, leaf chlorosis, and severe dwarfing of plants, and other symptoms. Because the feathery mottle virus is ubiquitous on sweet potatoes, the key is the transmission of chlorotic dwarf virus, and the chlorotic dwarf virus The transmission mediator is B. tabaci, and the flight distance of B. tabaci on sweet potato is very short. Therefore, removing SPVD and its surrounding sweetpotato plants can effectively control B. tabaci spread to surrounding healthy plants and control the spread of SPVD. Effective measures.
Epidemic Pathway: The disease was first discovered in China in 2009. In recent years, it has spread to almost all the main producing provinces of sweet potatoes, and there is a trend of further spread. Once the outbreak will cause inestimable loss of sweet potato production in China. The transfer of seed potatoes and seedlings is the main route for the spread and spread of SPVD over long distances, and must be paid great attention by potato farmers.
Prevention and control measures: For the major SPVD outbreaks in the main producing areas of sweet potato in our province, especially in Xiong County in 2016, we must start from the source and carry out systematic prevention and control. The sweet potato research team of Hebei Academy of Agricultural Sciences put forward the following prevention and control suggestions:
1. Choose seed potatoes. The nursery seedlings must be selected from seed potatoes that grow normally during growth and are not deformed when harvested. If the seedlings are found in the breeding field, there are yellow leaves, mosaics, shrinkage, cracks, etc. The seed potatoes produced in this plot are treated as re-sales. Seedlings used in nursery nursery for breeding seed potatoes must be selected for seedlings.
2. Grasp seedlings. As long as the potato seedlings are healthy, the SPV virus disease in the incubation period will not cause too much impact on the commodity potato. (1) Seedbed. In the general case of SPVD, it is recommended that conditional nursery households use the habitat every year (we have not planted sweet potatoes in the past five years and have not cultivated sweet potato plants). If SPVD has already occurred in the previous year, the breeding site must be changed at this year's nursery. (2) Seedbed management. During the seedling period, observe if there is a certain piece of fragile leaf, remove it together, and clean up the surrounding 30 cm of potato seedlings to remove the source of the disease. After each seedling is collected, spray the plastic film cover before the bed to prevent tobacco powder. Antimony and antiviral agents mixed liquid, whitefly control recommended imidacloprid or nicotine matrine, antiviral drugs recommended morpholine or Altai Ling (specific dosage can refer to the instructions). (3) SPVD training for picking seedlings workers should be conducted to ensure that diseased plants are cleared in time.
3. Strictly investigate. For the seed nursery for seed potato breeding, SPVD investigations are conducted about 20 days after planting. The diseased plants must be removed in a timely manner, and the healthy plants within 50 cm around are removed, and the disease is checked for 3 consecutive times at intervals of 10 days. Concentrated treatment of plants; commodity potato production fields, checking once on the 30th day after planting, and treating diseased plants collectively; seed potato breeding field, starting on the 20th day after planting, and checking and removing strains at the same time, 10 days apart, 3 times in succession Concentrated treatment of diseased plants.
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