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调查烟草花叶病的病情指数,过去是根据病状分级计算的。由于烟草花叶病的分级极为困难,调查时级别的估计不可能正确,而计算又较为复杂,同时轻斑驳在生产中的影响不显著,为此有采用新计算方法的必要。根据1963年7月在山东及辽宁调查的经验,认为下述几个因子应该作为计
The disease index for the investigation of tobacco mosaic disease was based on the grading of the disease in the past. Due to the extremely difficult grading of tobacco mosaic disease, it is impossible to correctly estimate the level of investigation and the calculation is rather complicated. At the same time, the influence of light mottling on production is not significant. Therefore, it is necessary to adopt the new calculation method. According to the survey conducted in Shandong and Liaoning in July 1963, the following factors should be considered as