| Experiment carried out to research the main disease and pests in tobacco young plant periods and the field of Bijie area, from 2003 to 2005. Results of the research indicated that tobacco virus (TMV, CMV and PVY), tobacco brown spot, tobacco granuville wilt, tobacco black shank, Root-Knot Nematodes, Helicoverpa assulta and Myzus persicae occurred lightly or partial lightly.Tobacco virus (mostly spread by Myzus persicae) had the trend of aggravation increasingly, the disease index was 0.16, 0.22 and 2.18 in the year of 2003, 2004 and 2005 respectively. The production value and out put of tobacco leaves reduced 3.43 and 2.635 percent respectively in 2005.Insect quantity of helicoverpa assulta was 2.3 heads every hundred tobacco plants, acreage of occurrence was 14000 hm2, The production value and out put of tobacco leaves reduced 1.59i and 1.2 per respectively in 2003. It was the highest occurrence disease of 2003.Degree of disease had the positive trend with the increase of spore quantity in air spread by tobacco brown spot, and the weather or other factors would affect the disease degree in tobacco fields. Tobacco brown spot began to happen in the first ten days of July, and then the disease index would increase. The fastigium of Helicoverpa assulta was the last twenty days of June, every hundred plants had 15 heads of insects in Dafang and 8 heads of insects in Jinsha.Display area of the comprehensive measures on the control of tobacco disease was 772hm2, the effect of virus disease control was 23.97, 26.67, 57.33 per in 2003, 2004 and 2005 respectively; the effect of Myzus persicae control was 53.31, 36.53 and 76.78 per respectively. The effect of tobacco black shank control was 92.73 per and tobacco granuville wilt control was 48.53 per in 2005. It totally reduced the economy losing about 1,130,000 yuan accumulatively and increased net income about 1,080,000 yuan. |
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