噻呋酰胺与吡唑醚菌酯复配对烟草靶斑病菌的抑制活性及对烟草靶斑病的室内防效

Antifungal activity of the combination of thifuzamide and pyraclostrobin against Rhizoctonia solani and its indoor control efficacy against tobacco target spot

由立枯丝核菌Rhizoctonia solani引起的靶斑病是近年来烟草主要叶部病害之一,严重降低了烟叶的产量和品质。目前生产中登记用于防治烟草靶斑病的药剂仅有井冈霉素,且该药剂对病害的田间治疗效果较差。为筛选对烟草靶斑病具有优良防效的化学药剂,本研究采用菌丝生长速率法建立了立枯丝核菌对噻呋酰胺和吡唑醚菌酯的敏感性基线,发现两者对立枯丝核菌菌丝生长均有较强的抑制作用。通过联合毒力测定发现两者复配后均表现为相加或增效作用,其中,噻呋酰胺与吡唑醚菌酯按质量比1:1复配,增效作用最明显,增效系数达2.5以上,可显著抑制病原菌菌核形成。采用喷雾接种法测定了该复配比作为保护剂和治疗剂使用时对烟草靶斑病的防效,发现其具有优异的室内防效。本研究结果表明,噻呋酰胺与吡唑醚菌酯按质量比1:1复配在田间防治烟草靶斑病中具有较好的应用前景。

Tobacco target spot(TTS)caused by Rhizoctonia solani is one of the major leaf diseases in tobacco in recent years,which significantly reduces the yield and quality of tobacco.However,only validamycin has been registered for TTS control to date,however,its curative activity in fields is relatively low.To screen chemical fungicides with high antifungal activity against R.solani,the sensitivity baseline of R.solani to thifuzamide and pyraclostrobin was established by the mycelium growth inhibition assay,respectively.When tested alone,both thifuzamide and pyraclostrobin exhibited high antifungal activity against R.solani mycelial growth.The allied toxicity assays showed that the combinations of thifuzamide and pyraclostrobin have either additive or synergistic effects.A mixture of thifuzamide and pyraclostrobin(m/m,1:1)exhibited the best synergistic inhibition of mycelial growth with a synergistic coefficient of above 2.5 and significantly inhibited the formation of sclerotium.The spray inoculation method was used to evaluate the protective and curative activities of the mixture to TTS and the result showed that the mixture has excellent indoor control efficiency.Taken together,these results indicated that a mixture of thifuzamide and pyraclostrobin(m/m,1:1)had good potential in TTS control in the fields.