水稻纹枯病防治药剂配方筛选及其剂型的研制

以水稻纹枯病菌(Rhizoctonia solani)为供试菌,采用菌丝生长速率法,研究比较了5种新型杀菌剂的室内毒力,并选用高效单剂进行复配研究,明确最佳配比;根据药剂理化性质选用流点法、黏度曲线法和正交试验设计法将混剂加工成对环境友好的水悬浮剂。结果表明:5种杀菌剂中对水稻纹枯病菌的毒力(有效中浓度,EC50)由高到低顺序为:嘧菌酯(0.005 19μg/ml)、已唑醇(0.025 20μg/ml)、戊唑醇(0.209 10μg/ml)、丙环唑(0.349 70μg/ml)、苯醚甲环唑(0.777 10μg/ml);毒力最高的嘧菌酯与己唑醇复配的最佳配比为1∶2(增效系数SR值为1.55);嘧菌酯.己唑醇悬浮剂的最优配方组成为:8.0%嘧菌酯、16.0%己唑醇、2.0%分散剂550s、2.0%农乳404#、0.125%黄原胶、1.5%硅酸镁铝。

Screening of fungicides combination against rice sheath blight and development of its formulation

Toxicities of five new fungicides(azoxystrobin,hexaconazole,tebuconazole,propiconazole and difenoconazole) to rice causal agent Rhizoctonia solani were tested using mycelial growth rate method.The laboratory toxicities of the mixture of the strongest-toxicity fungicides were detected,and the optimal ratio was studied.The mixture was then processed into environmental-friendly suspension concentrate according to physical and chemical properties of the fungicides using flow point method,viscosity curve and orthogonal test.Among the five fungicides,azoxystrobin showed the highest toxicity to Rhizoctonia solania with the median effect concentration(EC50) value of 0.005 19 μg/ml,followed(in order of toxicity) by hexaconazole(0.025 20 μg/ml),tebuconazole(0.209 10 μg/ml),propiconazole(0.349 70 μg/ml),and difenoconazole(0.777 10 μg/ml).The optimum ratio of azoxystrobin to hexaconazole was 1∶2,and the joint synergetic ratio was 1.55.The optimum formulation of 24.0% azoxystrobin-hexaconazole suspension concentrate was 8.0% azoxystrobin,16.0% hexaconazole,2.0% dispersant 550s,2.0% pesticide emulsifier 404#,0.125% xanthan gum(XG),1.5% magnesium aluminum silicate.