草莓丝核菌根腐病病原菌鉴定及7种杀菌剂的抑菌作用测定

Identification of Rhizoctonia species causing root rot of strawberry and inhibition effects of seven fungicides

为了解草莓丝核菌根腐病的病原种类及筛选防治丝核菌根腐病的有效杀菌剂,本研究基于形态学特征、细胞核荧光染色、菌丝融合群测定以及rDNA-ITS的序列分析,对北京和河北承德地区的草莓丝核菌根腐病的病原菌进行了鉴定,并利用菌丝生长速率法测定了7种杀菌剂对丝核菌的抑菌作用。结果发现,北京地区的丝核菌为双核丝核菌(binucleate Rhizoctonia,BNR),属于融合群AG-A;河北的丝核菌为立枯丝核菌Rhizoctonia solani,属于融合群AG-4。氟啶胺、吡唑醚菌酯、噻呋酰胺、戊唑醇、咯菌腈、氟硅唑对2种丝核菌均有很强的抑制作用,EC 50值为0.063 9~2.485 7μg/mL,抑霉唑的抑制作用较差,EC 50值为9.966 8~11.236 8μg/mL。同一种杀菌剂对不同丝核菌的抑制作用存在差异,噻呋酰胺、戊唑醇、氟硅唑、咯菌腈和抑霉唑对立枯丝核菌的抑制作用强于对双核丝核菌。试验结果为生产上合理选用杀菌剂防治草莓丝核菌根腐病提供了科学依据。

In order to identify the pathogens causing Rhizoctonia root rot of strawberry and select efficient fungicides for controlling the disease,the pathogen of the diseased samples from Beijing and Chengde,Hebei province was identified based on morphology,nucleus fluorescence staining,hyphal anastomosis test,and rDNA-ITS sequence analysis.The inhibition effect of seven fungicides on the Rhizoctonia isolates was also determined by mycelial growth rate method in this study.Binucleate Rhizoctonia AG-A and R.solani AG-4 were identified as the pathogens from Beijing and Hebei,respectively.Fluazinam,pyraclostrobin,thifluzamide,tebuconazole,fludioxonil and flusilazole showed very strong inhibition against the two Rhizoctonia species with the EC 50 values ranging from 0.063 9 to 2.485 7μg/mL.Imazalil had higher EC 50 value from 9.966 8 to 11.236 8μg/mL.The inhibition of different Rhizoctonia species by the same fungicide varied.Thifluzamide,tebuconazole,flusilazole,fludioxonil and imazalil showed stronger inhibition against R.solani than binucleate Rhizoctonia.The results provide a scientific basis for using fungicides to control Rhizoctonia root rot in strawberry production.