10种药剂对尖孢镰刀菌的抑菌活性及抗药性风险评估OA

[Objective]This study was conducted to determine the sensitivity baseline of Fusarium oxysporum from major tobacco-growing regions in China to commercially available fungicides.[Method]Fusarium oxysporum was isolated and purified from 218 tobacco root rot samples collected from Guangxi,Guizhou,Anhui,Fujian,and Jiangxi.The toxicities of 10 fungicides were evaluated by using the mycelial growth rate method.Isolates were categorized as sensitive,low-resistant,moderately resistant,or highly resistant based on resistance indices,and resistance frequencies were calculated.[Result]45%of cyclobutrifluram was only detected in sensitive and low resistant individuals,with an average EC50 of 0.042 µg/mL and the highest inhibitory activity.The average EC50 of 30%trifloxystrobin tebuconazole and 20%pydiflumetofen difenoconazole were 0.621 µg/mL and 0.207 µg/mL,respectively,with sensitive strains accounting for over 60%.The average EC50 values of 40%difenoconazole pyraclostrobin and 60%boscalid fludioxonil fungicide were 0.423 µg/mL and 4.463 µg/mL,and the proportion of sensitive strains in Longyan and Sanming areas was lower than that in other areas.29%isopyrazam azoxystrobin EC50 reached 358 µg/mL,with sensitive strains<50%and cumulative medium high resistance>30%.The resistance frequencies of 25%pyraclostrobin and 25%pyrisoxazole exhibited"inverted pyramid"resistance structure,with high resistance frequencies reaching 30%and 20%,respectively.[Conclusion]45%cyclobutrifluram can be used as a core rotation agent for the prevention and control of Fusarium oxysporum wilt disease in tobacco growing areas.Agents with"bimodal"or"inverted pyramid"patterns should be immediately discontinued and the baseline monitoring should be established in different zones.Combining different mechanisms of mixing and biological agent rotation can delay the fixation of highly resistant individuals and ensure sustainable disease control.