目前,在药效试验中,一般以绝对防效或相对防效计算防病效果。绝对防效法计算简单,但不能反映病情的发展趋势,因而多用相对防效法计算效果,但这种方法只适用于计算保护型杀菌剂对病害的效果,对治疗剂其防效可能超过100％(原因是处理区药后病指比基数病指小,增长率为负数),在理论上就不可理解。1983年,采用粉锈宁防治小麦白粉病就出现 At present, in the efficacy test, the general anti-disease effect or relative anti-disease effect calculated. The absolute anti-efficacy method is simple, but it can not reflect the development trend of the disease. Therefore, the relative anti-efficacy method is mostly used to calculate the effect. However, this method is only suitable for calculating the effect of the protective anti-microbial on the disease. The reason is that after treatment, the disease index in the treatment area is smaller than the base disease index and the growth rate is negative), which is not understandable theoretically. In 1983, the use of triadimefon to control wheat powdery mildew appeared