生防潜力菌H158与杀菌剂混配对水稻纹枯病菌毒力增效作用

Synerg istic Effects of Potential Biocontrol Bacterium H158 Mixed with Fungicides Against the Pathogen of Rice Sheath Blight Rhizoctonia solani

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%。

The toxicities of Jinggangmycin A and boscalid, as well as their mixture, against the pathogen of rice sheath blight Rhizoc-tonia 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%.