Tests in both lab and fields indicated that metalaxyl resistant isolates appeared and the effectiveness of metalaxyl on late blight disease were weakened.

• 室内菌株测定和田间试验,均证明抗瑞毒霉菌株的存在,导致瑞毒霉防效降低,但是它的复配药剂瑞毒霉锰锌仍保持很高的防效;