Abstract: The toxicities of Jinggangmycin A and boscalid, as well as their mixture, against the pathogen of rice sheath blight Rhizoctonia solani were investigated by using the method of inhibition mycelial growth rate. The results showed that EC50 of Jinggangmycin A and boscalid were 114.0672 mg/L and 0.0569 mg/L, respectively, and EC50 of mixture of Jinggangmycin A and boscalid at rate of 1:100, 1:200, 1:300, and 1:400 were 5.5814 mg/L, 6.8186 mg/L, 5.2672 mg/L and 2.7772 mg/L, respectively. Co-toxicity index of these mix rates were 0.9716, 1.5182, 2.8210, and 6.8325, which means that almost all of the mixtures exhibited synergy effect, except the mix rate of 1∶100 showing additive effect. Boscalid showed little inhibition effect against the bacterium H158 at the concentration as high as 1.6 mg/ml. H158 can only be inhabited by Jinggangmycin A at higher concentration, however mixture of Jinggangmycin A and boscalid showed little inhibition effect against H158, the control efficient of which can be enhanced to more than 90%.  

Key words: validamycin A, boscalid, potential biocontrol bacterium H158, rhizoctonia solani, Co-toxicity index

摘要： 采用菌丝生长速率法，分别测定了井冈霉素A、啶酰菌胺及两者间混配的毒力系数，及对生防潜力菌H158繁殖、生长的影响。结果表明，啶酰菌胺+井冈霉素A按1∶100、1∶200、1∶300和1∶400比例混配，对水稻纹枯病菌（Rhizoctonia solani）的EC50分别为5.5814、6.8186、5.2672、2.7772 mg/L，共毒系数分别为0.9716、1.5182、2.8210、6.8325，除1∶100表现为协同作用外，其他混合比例对纹枯病菌均表现为增效作用。啶酰菌胺对生防潜力菌H158的生长抑制作用不大，低浓度井冈霉素A对H158表现为相容性，较高浓度时有一定抑制作用。但两者混配药剂中加入H158，对其抑制情况与啶酰菌胺相似。混配剂中加入H158后对纹枯病菌的抑制率比未加H158时有所提高，均高于90.00%。

关键词: 井冈霉素A, 啶酰菌胺, 生防潜力菌H158, 水稻纹枯病菌, 毒力系数