Studies On Occurrence Regularity And Control Technology Of Potato Virus Y Disease In Qiannan Tobacco Growing Areas

In Guizhou Province Qiannan autonomous prefecture, tobacco potato virus Y (PVY) disease hazards is increasing year by year, has become the main diseases of Tobacco in Qiannan, seriously affect tobacco yield, quality and economic benefit, to endanger Tobacco Production persistence development in Qiannan.For this reason, our research team to investigate incidence of Tobacco Potato Virus Y disease in Qiannan in2010, use serological and molecular methods for identification of the strain of potato virus Y, survey found that, in Weng’an, almost all of the tobacco fields are hazardsed by the PVY, field investigation found that the PVY strain rate for more than20%, partial plots up to70%, Liuchang dam even crops.201tobacco samples were collected from Guizhou Province Qiannan tobacco producing areas which have significantly Potato virus Y disease symptoms, in2010. Using Tas-ELISA to detect the three lines PVYN, PVYO and PVYC of PVY, the results showed that171samples were detected out in201samples by PVY infection, which PVYN37, accounting for21.6%; PVYO133, accounting for77.8%; PVYN and PVY0Mixed infection1, accounting for0.6%. PVY strains distributed with a certain regularity, in Qiannan, PVYO strains is main strains, PVYN have relatively small infection, PVYC were not detected in all samples, mixed infection sporadic occur.Infected with PVY, tobacco samples are collected from the Guizhou Province Qiannan autonomous prefecture Tobacco raise District, use the Trizol method, total RNA of samples is extracted, RT-PCR amplification, cloned and sequenced of PVY CP gene. The results showed that the cloned cDNA fragment have1078bp specific nucleotide composition that contains an801bp open reading frame (ORF) encoding266amino acids.17PVY strains nucleotide sequence of PVY in Qiannan with17other PVY strains nucleotide sequence homology of86.6%-99.9%in GenBank. The systematic relationship tree analysis showeded that the19PVY separation from Qiannan tobacco samples, PVY16, accounting for84.2%; There are three PVYN, accounting for15.8%, PVYC0, According to the the identified results found, infested tobacco PVY in area of Qiannan, PVY is main strains, relatively small PVY infection, molecular identification results are consistent with the results of ELISA.The virus seriously genesis area in Qiannan tobacco, on main virus-source plants infected by virus, virus species identification study. The main virus-source plants were collected from the tobacco virus disease serious area in GuiZhou province QianNan prefecture, detected by Tas-ELISA and indirect ELISA for two kinds of plant viruses CMV and PVY, which were conveied by aphids. The results showed that there were54samples infected by the viruses in165virus-source plants, in which29by CMV, attained17.58%;25by PVY, attained15.15%;9by CMV and PVY, attained5.45%. The economics field crops contained potato, brassica napobrassica and the weeds contained strawberry, geranii, veronica, Indian kalimeris herb, cephalanoplos segetum Kitam, plants of the mugwort, annual fleabane herb and so on could be infected by CMV and PVY, in which potato was the more serious tox-source plants.In Qiannan PVY illness District, aphids Occurrence study, the amount of, in Qiannan tobacco fields, alatae and aphid with infection rate and tobacco incidence was directly positively correlated. Amount and infection rate was positively correlated directly and tobacco incidence for the occurrence of local aphid occurrence and prevention research, study showeds Qiannan tobacco area wingless aphids peak period occurs mostly in late May to6mid-May, late June, a significant reduction. The Qiannan tobacco area winged aphids occurred peak period are mostly concentrated in early May to early June, there are the winged aphids activities are more frequent in the entire May, May be winged aphids migrating peak of Qiannan early June significantly reduced.Seedling stage is the most susceptible period of tobacco, once the flu illness will incidence of plant and viral disease sooner, the greater will be the loss, so the seedling stage must be good sources of drugs control is to control the seedling stage aphidshazards, take Clear of greenhouses surrounding weeds and bridges host insect nets isolation, yellow Card Traps and the silver film repellent chemical control and integrated control measures, can significantly reduce the ability of aphid-borne PVY.Finally, a serious illness District made prevention and control research, to obtain the desired results, investigation Weng’an County the cultivation mode tobacco potato virus Y diseased plants rate. The results found that single line with wheat smoke, the smoke of a single line of silver membrane smoke and single onion sets the average plant rate (4.1%-8.1%) was significantly lower than the double line with wheat smoke, single albuginea smoke, the smoke of the open field and two-line black film smoke the average plant rate (17.3%-50.1%), of which the lowest single line wheat smoke average plant rate, only4.1%, double lines of black film smoke average plant rate is the highest, reaching50.1%. According to the survey results, it is recommended to promote single line wheat tobacco cultivation mode is seriously ill Ward in Weng’an County Tobacco potato virus Y.