苹果炭疽病初发期病株、病果率的测定,习惯上通用排列组合随机取样,这种测定法可以在少量的取样中,迅速测定出大面积果区的病情。但是这种测定法测出的数据,往往与实际病情有较大的差误。现用普查法与之对比结果如下: 在80株供试树中,用目测数出全部病株、病果。计有病树11株,病株率为13.7％有果44160个,其中病果94个,病果率为0.021％。而采用排列组合随机取样法,其结果则因取样次序而异: Apple anthracnose initial incidence of diseased plants, the determination of the rate of disease, the habit of a universal array of random sampling combination, this assay can be a small amount of sampling, the rapid determination of a large area of ​​the disease area. However, the data measured by this assay often have a large discrepancy with the actual condition. Comparison of the results of the current census results are as follows: 80 test trees, visual inspection of all diseased plants, fruit. The total number of diseased trees was 11, and the diseased plants rate was 13.7% and fruit 44,160, of which 94 were disease and the disease rate was 0.021%. The use of permutation and random sampling method, the results vary with the sampling order: