丁香菌酯与咪鲜胺对水稻纹枯病菌的协同作用

Synergistic effects of coumoxystrobin and prochloraz on Rhizoctonia Solani Kühn

【目的】研究丁香菌酯和咪鲜胺及其组合对水稻纹枯病菌的作用效果及对该病害的田间防治效果,为田间防控水稻纹枯病提供理论依据。【方法】在室内离体条件下,以水稻纹枯病菌为材料,采用菌丝生长速率法测定丁香菌酯和咪鲜胺原药及其组合对水稻纹枯病菌的生物活性,筛选出最佳配比,初步分析该组合对纹枯病菌的增效机制;根据最佳配比,进行田间防效试验。【结果】丁香菌酯和咪鲜胺原药单剂对水稻纹枯病菌菌丝生长均具有较好的抑制作用,有效抑制中浓度(EC_(50))分别为1.47和0.61μg/mL。丁香菌酯与咪鲜胺原药以质量比1∶4、1∶2、1∶1、2∶1、4∶1进行组合时对纹枯病菌菌丝生长均具有抑制作用,EC_(50)在0.12~0.24μg/mL;其中,丁香菌酯与咪鲜胺以质量比4∶1组合时增效作用最明显,其EC_(50)为0.12μg/mL,共毒系数(CTC)为955.81。田间试验结果显示,20%丁香菌酯SC与25%咪鲜胺EC以有效成分用量比4∶1组合(48 g/ha+12 g/ha),药后21 d对水稻纹枯病的防治效果高达84.85%,极显著高于20%丁香菌酯SC(73.58%)和25%咪鲜胺EC(72.79%)单剂的防治效果(P<0.01)。丁香菌酯与咪鲜胺以质量比4∶1组合能提高纹枯病菌细胞膜的通透性、破坏细胞膜的完整性、增加可溶性蛋白含量。【结论】丁香菌酯与咪鲜胺以有效成分用量比4∶1组合的增效作用明显,对水稻纹枯病有较好的协同防治作用,且明显减少药剂的使用量,有开发成水稻纹枯病增效制剂组合的潜力。

【Objective】The purpose of the study was to investigate the effect of coumoxystrobin,prochloraz and their combination on Rhizoctonia solani Kühn,and the field control efficacy of this disease,so as to provide theoretical basis for the field control of rice sheath blight.【Method】Used R.solani as material in the indoor in vitro condition,the bioacti-vity of coumoxystrobin TC and prochloraz TC and their combination against R.solani was determined by mycelium growth rate method.The optimal ratio was screened out to preliminarily analyze the synergistic mechanism of the combination against rice sheath blight.According to the optimal ratio,the field efficacy tests were carried out.【Result】The results showed that coumoxystrobin TC and prochloraz TC single dosage had good inhibitory effects on the mycelial growth of R.solani,and the effective inhibitory concentrations(EC_(50))were 1.47 and 0.61μg/mL respectively.The combination of cou-moxystrobin TC and prochloraz TC at the mass ratios of 1∶4,1∶2,1∶1,2∶1 and 4∶1 had inhibitory effects on the myce-lial growth of R.solani,and the EC_(50)was in the range of 0.12-0.24μg/mL.Among them,the synergistic effect was most significant when the combination of coumoxystrobin and prochloraz at the mass ratio of 4∶1,with an EC_(50)of 0.12μg/mL,and a cotoxicity coefficient(CTC)of 955.81.Field test results showed that the combination of 20%coumoxystrobin SC and 25%prochloraz EC with the active ingredient mass ratio of 4∶1(48 g/ha+12 g/ha)had a high control effect of 84.85%on rice sheath blight at 21 d post-dose,which was extremely sgnificantly higher than the control effects of 20%coumoxys-trobin SC(73.58%)and 25%prochloraz EC(72.79%)as single agent(P<0.01).The combination of coumoxystrobin and prochloraz with the active ingredient mass ratio of 4∶1 could improve the permeability of cell membrane of R.solani damage the integrity of the cell membrane,and increase the content of soluble protein.【Conclusion】The synergistic effect of the combination of coumoxystrobin and prochloraz with the active ingredient mass ratio of 4∶1 is significant,and it has a better synergistic control effect on rice sheath blight,and greatly reduces the amount of pesticides used.It has the poten-tial to be developed into a combination of synergistic preparations for rice sheath blight.