Distribution And Identification Of The Tobacco Fungal Disease In Chongqing

Tobacco is an important economic crop in China. The disease, especially fungal diseases occurred on tobacco severely reduced yield and quality, and then limited the development of the tobacco. In order to identify the species of tobacco fungal diseases and its distribution, improve the description of disease symptoms and the pathogen morphological character, advance in recognizing tobacco fungal disease in the field, provide theoretical criteria for disease control in Chongqing. Pathogen morphological character as well as symptoms of11fungal diseases, and the distribution of them was described in this paper. Among these diseases,2fungal diseases were first records in Chongqing,2fungal diseases of which were new records on tobacco. The primary results are as follows:1. The identification of general tobacco fungal diseases in ChongqingFor diseases had been reported, a method of combining the disease symptoms and pathogen morphological character would be adopted. The result showed that8tobacco fungal diseases were identified. These diseases included Tobacco grey mould (Botrytis cinerea Pevs.), Tobacco powdery mildew (Erysiphe cichoracearum DC), Tobacco black shank (Phytophthora parasitica var. nicotianae (Breda de Hean) Tuker), Tobacco brown spot (Alternaria alternata (Fries) Keissler), Tobacco anthracnose(Colletotrichum nicotianae Av.-Sacca), Tobacco phyllosticta leaf spot(Phyllosticta tabaci Pass.), Tobacco ragged leaf spot (Ascochyta nicotianae Pass.), Tobacco broken leaf spot (Mycosphaerella nicotianae (Ell. et Ev) Mils). Among them, Tobacco broken leaf spot was recorded for the first time in Chongqing.2. The identification of unknown pathogens and new tobacco fungal diseasesThe unknown pathogens and new diseases were identified based on symptoms caused, pathogen morphology observation, pathogenicity test and gene analysis (rDNA ITS or β-tubulin). The results showed3fungal diseases were identified. Among these diseases, Falcate-conidia anthracnose of tobacco (Colletotrichum dematium (Pers. ex Fr.) Grove) was second report in China, following the first report in2011in Shandong. The two new tobacco diseases caused by Phoma sp. and Epicoccum sp. were reported for the first time on tobacco.3. The distribution of tobacco fungal diseases in ChongqingDiseases were investigated, and the data of its quantities and distribution were summarized from2010to2013.13fungal diseases were recorded and their pathogens were identified. Among these diseases, Tobacco ragged leaf spot and Tobacco phyllosticta leaf spot were mainly distributed. The rate of sample quantities was28.8%and23.4%respectively. Then Tobacco black shank and Tobacco brown spot were secondly distributed in Chongqing. The rate of sample quantities was19%and18.5%respectively. In Chongqing,4fungal diseases were first records. Among those diseases, Tobacco broken leaf spot only found in Nanchuan and Wanzhou. Falcate-conidia anthracnose of tobacco only found in Qianjiang. New tobacco disease (Phoma sp.) found in Wulong and Pengshui. Another new tobacco disease (Epicoccum sp.) only found in Pengshui. At the same time, with the statistics of diseases types in each area, we found there was a little difference among them. In these areas, Qianjiang, Fuling, Fengjie, Wulong, Wuxi, Nanchuan had more diseases types.