一、调查方法 在不同立地类型的杉木林病区内,按同一立地条件下选灰杉30株,随之又在每株灰杉之旁再选黄杉一株与灰杉对比。对每株杉木均采用随机抽样法勾取下部及中部枝条各5个。从每个枝条上取去年秋梢及今年春梢叶片各20片。然后,对每株选取的400个叶片上分别统计感炭疽病的叶片数及因炭疽病而枯白叶片数。 First, the survey method In the different types of Chinese fir forest ward, 30 under the same site conditions selected lily, followed by re-selection of each plant next to the gray fir Sequoia Contrast. For each cedar, random sampling was used to check the lower and middle branches of 5 each. Take the autumn shoots from each branch and 20 leaves of spring shoots this year. Then, the number of leaves of anthracnose and the number of withered leaves due to anthracnose were counted on 400 leaves of each plant.