| Known as "plant cancer", viral diseases have caused severe losses to agricultural production as its diversity and wide range of hosts. Tobacco mosaic virus disease (TMVD) is consist of several plant viruses (such as TMV, CMV, PVY) and broadly dispersed among most tobacco-planting areas. Tobacco mosaic virus (TMV) was the most common disease among TMVD, which would damage tobacco productivity seriously in most tobacco areas across our country. In this study, indoor bioassay and pilot trails were conducted, in which viral inhibitors Ningnanmycin and plant resistance inducer, such as Oligosaccharins, trace element Zinc sulfate were selected as basic materials, optimized blending ratio and concentration of compounded pesticides were determined after tests such as ratable optimum of compound pesticides, concentration and evaluation of control effects against TMVD, and explore the host physiological effect after different treatments, which would provide certain references for effective control of viral diseases on tobacco. The main conclusions were as follows:1. Screening test of prescription and concentration of NOZ (Ningnanmycin-Oligosaccharins-Zinc Sulfate) were conducted by Indoor potted experiments. Results showed that the EC50 of Ningnanmycin (40%) and Oligosaccharins(80%) were 534.17 mg/L and 13.01 mg/L, respectively. The joint-toxicity was obtained as m:m=9:1, the spraying concentration 76.54 mg/L. Trace elements, such as zinc sulfate was added into the compounded agent as to enhance the plant resistance. Finally, we chose 9:1 as the final quality ratio (Ningnanmycin vs Oligosaccharins) for applying, the final concentration was 76.54 mg/L, added by zinc sulfate,150 mg/L.2. Indoor potted growth experiment about the effect of NOZ (Ningnanmycin, Oligosaccharins and Zinc sulfate) against tobacco mosaic virus disease. 10d after the last spraying, the control effect showed no significant difference (P> 0.05) among NOZ, Ningnanmycin and Oligosaccharins, the control effect of NOZ is perfect about 46.97%, But their the control effect decreased with the time going by, a significant difference (P<0.05) emerged 20d after spraying, of which NOZ performed the best role in controlling the diseases, that was 34.53%.3. Indoor evaluation of NOZ to tobacco plant physiology. While the optimized ratio was obtained, the activity of some resistance-relevant enzymes inside of tobacco plants could be improved to some extent after spraying. According to the test, chlorophyll level changed significantly (P<0.05) while Ningnanmycin and Oligosaccharins were not (P>0.05). POD was increased but not too much as still under the significant level (P>0.05). CAT showed some improvement and significant difference compared with other treatments (P<0.05). SOD activity value was lower than Ningnanmycin and Oligosaccharins but higher than positive control (TMV treatment), it showed significant difference (P<0.05) compared with TMV negative control rather than positive control (P>0.05).4. Control effect test of NOZ in the field. NOZ was sprayed via power sprayer to tobacco plants at 7d before and 7d after transplanting and 10d later in interval. We found that NOZ performed better than other agents. In the final survey, NOZ displayed a significant difference (P<0.05) compared with other treatments such as 8% Ningnanmycin AS,0.5% Oligosaccharins AS and 8% Ningnanmycin+0.5% Oligosaccharins AS, but not 8% Ningnanmycin+0.5% Oligosaccharins+ zinc sulfate treatment. In addition, the NOZ treatment have promotion affect to tobacco’agronomic traits. In the early stages of TMV disease, most tobacco agronomic traits treated by NOZ were less well than those of commodity mixed pesticides, but better than that of 8% Ningnanmycin and 0.5% Oligosaccharins alone. Significant difference of NOZ only occurred during the 3-5 leaves period when the average leaf width was notably better than the treatment of 0.5% Oligosaccharins (P<0.05) The promotion of agronomic traits stimulated by NOZ was more significant (P<0.05) than those of 8% Ningnanmycin and 0.5% Oligosaccharins. The difference of promotion effect had an increasing trend, but the difference among NOZ,8% Ningnanmycin+0.5% Oligosaccharins,8% Ningnanmycin +0.5% Oligosaccharins+Zinc sulfate treatments was not significant. (P>0.05). |
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