Studies On Tobacco Anthrax Strains Of The Pathogenic Form, Pathogenicity And Prevention

This paper is the study of the six strains of the pathogenic form, pathogenicity and prevention and control which is isolated from Yongzhou, Chenzhou, Changsha, Shaoyang, etc. The study has shown that:the 6 tested strains belong to the same species of Colletotrichum nicotianae A verna-Sacca, but these different strains are divergent in pathogenicity on tobacco K326. Meanwhile the selected 50% dimethachlon powder can be dominant 500 times,5% thiophanate 500-1000 times, 70% mancozeb 500 times,7% chlorothalonil 250 times are effective agents to combat disease.1.In the first 4days,the tobacco K326 which were inoculated the six isolated tested strains have been all diseased,after the first 7 days the tobacco K326 have the performance of the typical type of lesions in acute anthrax.2. The tested strains are consistent in molecular spore plates, setae, conidial shape and size.Comparing with Colletotrichum nicotianae Averna-Sacca, the size of the pathogen are the same, but the cultivation characteristics of the tested strains are slightly larger than the Colletotrichum nicotianae Averna-Sacca.3. The tested strains in virulence on tobacco K326 showed inconsistent.3 days after vaccination one strong virulence strain has the disease,7 days after inoculation the disease index is as high as 95.8. A weaker strain of pathogenic bacteria is starting the disease in the next 4 days,7 days after inoculation the disease index is only 20.0.4. By indoor screening test of Fungicide, the four types of agents such as 50% dimethachlon WP,50% thiophanate-methyl WP,70%Mancozeb WP and 75% of the chlorothalonil WP have good antimicrobial effect on Tobacco anthrax, just not the same as the use of concentration, the antibacterial activity of the performance there are some differences.5. By the pharmaceutical laboratory and field tests,the screened out of 50% of the dimethachlon powder can be dominant 500 times,5% thiophanate 500-1000 times, 70% mancozeb 500 times,7% chlorothalonil 250 times have more pronounced effects on tobacco prevention and treatment of anthrax. 6. By first spraying bacteria after inoculation and the first spraying as well as using drug contrasting before the initial onset of the field with after the onset, the results from the control point of view, the occurrence of anthracnose of tobacco hazard prevention, we must to seize an "early" word. While the agricultural control is the basis, the chemical control is the supplement. It is important to not only prevent the use of pesticides to the environment due to pollution, but also reduce production costs for the farmers.It is conducive to the sustainable production and management of land.