Tobacco Mosaic Virus Diseases' Generation And Their Chemical Protective Mechanism

Tobacco, one of the important economic cultivars, is widely planted in the world. It is always infected with many diseases, especially with tobacco virus diseases which are prevalent in all the tobacco-planted areas, including our country. It's estimated that more than 100 million dollars were lost only by TMV every year in the world. Recently, because of increasing tobacco-planted area and changing crop distribution, the numbers of virus resources and transmission vectors are increasing. So are the infection and the harm. This tendency is developing. They become the main restrictive factors in tobacco's output and quality. In this paper, we surveyed the main virus resources, which infected tobacco in Shannxi, and illuminated their generation, prevalent trend and harm. By use of new kind of plant virus inhibitor -Bilken virusicide, we test its in-room and sectional biotic control effect, the host's tissue pathology change and its chemical protective mechanism. The results are as follows:1) Virus sources which cause tobacco virus diseases in Shannxi are mainly 4 types: TMV, CMV, TEV and PVY. They are all transmitted by aphids except TMV. The mixed invasion is popular. For example, TMV and CMV disease always happen together and cause serious mosaic. Because of the complex situation, synthetic protective measures should be used.2) The tissue pathological changes of the host leaves, which are infected with TMV indicated virus-resistant mechanism of 3.95% Bilken virusicide WP. It maked virus inert, inhibited virus from multiplying, reduced the quantity of virus in the cell of mesophy, and protected chloroplast from disorganization. The granuloses expanded and accumulated in chlorophyll and the number of Osmiumphile bodies increased, all of which increase the disease-resistant ability.3) The chemical control effect of 3.95% Bilken virusicide WP to TMV. In-room experiments indicated that it can strongly resist TMV; The sectional control showed that the control effect was better in the beginning of the disease and in the period of seeding, and the best concentration is 500.4) The effective elements of 3.95% Bilken virusicide WP have the powerful inside-suck and transmittable capacity. They can control the virus by making virus inert, resisting virus to multiply, motivating and increasing the plant resistance. It will be very helpful to continue studying the control mechanism of TMV in agriculture production.5) It is reported by National Tobacco viruside effect web experiment that in 2001 and 2002 the best average control effect in the viruside all over the country is Bilken virusicide. Moreover, Bilken virusicide is effective, wide-ranging and low-toxicand. It has good applied value an is worthy being recommended.