Studies On The Investigation,Identification Of Tobacco Diseases And Integrated Control Of Major Tobacco Diseases In Xiangxi

Tobacco is an important economy crop in our country,but all cultivars of tobacco are inevitably affected by the diseases in the cultivation,and tobacco diseases has become a major constraining factor in tobacco production.There are a serious disease of tobacco now,such as Tobacco Virus diseases,Tobacco Black Shank, Tobacco Bacterial Wilt,Tobacco Brown Spot,and so on.Tobacco Bacterial Wilt in tobacco-growing areas of the South has been particularly severe.Therefore,clear about the occurrence of the disease on tobacco,is very important to reduce losses which caused by diseases.In this paper,investigation,detection and pestiside controlling test were described in details about tobacco diseases in Xiangxi.There also had a study on major tobacco disesses with integrated controlling.Through the investigation,a total of 4 kinds of infectious diseases were found in the seedbed period,those were,Pythium aphanidermatum,Colletortichum nicotianae, Virus diseases and Rhizoctonia solani.The Pythium aphanidermatum was the most serious disease in the period of seedbed in Xiangxi,the greenhouses number of incidenced accounted for 42.8 percent of the total number of surveys,each county has taken place.A total of 10 types of disease had been found in autumn,of which 3 kinds were infected by fungi:brown spot,black shank,broken leaf spot;3 kinds of bacterial diseases:bacterial wilt,wildfires and air stem disease;3 kinds of virus diseases: Mosaic virus(contains CMV and TMV),tobacco etch virus(TEV) and potato virus Y(PVY);there was also a climate leaf spot caused by the climate.The TEV and PVY were only found in Fenghuang.Under the premise of deleting the instance which diseases occurred complexly, the disease occurred in an area about 5760 hm~2,accounting for 55.38 percent of the cultivated area,the loss of an area about 986.7 hm~2,the total acreage of the state of 9.49 percent in 2007.The virus were detected by ELISA method in laboratory.The results showed that TMV,CMV and PVY were not detected in 110 seedlings samples.There only detected TMV from three soil samples in Huayuan,CMV was not detected. The major kinds of tobacco virus diseases in field were TMV,CMV infection and its complex infection in Xiangxi,these three types of infection account for the measured samples of 96.3 percent,with the highest frequency of infection was TMV,a separate and the compound infection account for 90.6 percent.Among the 5 kinds virus which have been identified,TEV and TRSV only occurrenced in a few sporadic region.The results of tobacco brown spot pestiside controlling experiment showed that, Jinyeshu,Baofengning,Chibante,Huihening,Junke,Dimetachlone(ck),these 6 kinds of pharmaceutical test of efficacy is more than 60%,in particular,the efficacy of Huihening,Junke and Chibante was retained at 80%,better than the other three pestisides.The results of tobacco virus disease pestiside controlling experiment showed that,the top four average efficacy among 13 kinds of pestisides were fllowing: Dongwangshadu(68.4%),Fushizhuang(61.9%),Jingtuling(61.1%),Bingdute(60.6%).However,the results of tobacco bacterial wilt pestiside controlling with four different pestisides were not satisfactory.The efficacies of pestisides were better in the early time,the highest efficacy was 50.12%(72%agricultural sulfate streptomycin), but the latter effect is not ideal.On the whole,72%agricultural sulfate streptomycin had a relatively good effect.There had a study on major tobacco disesses with integrated controlling in Longshan Xiangxi in 2007.The results indicated that the efficacy in integrated controlling zone was 83.50%,conventional controlling zone was 80.53%,the efficacy in integrated controlling zone is 2.97%higher than conventional controlling zone.Colligating results,the diseases loss was under 10%in the integrated controlling zone,the cost of pestiside was average 684 yuan per hm~2,below the anticipative goal of 750 yuan per hm~2.Compared with conventional controlling zone,had been saved 315 yuan per hm~2,and the efficacy for major tobacco diseases was higher,so as to achieved a purpose to use pesticides rationally and advanced the efficacy for major tobacco diseases.