Analysis of diffusion path of carbendazim-resistance population of Fusarium head blight——based on Fusarium species,mycotoxin chemotype and resistance timing

By the identification of species of carbendazim (MBC) resistant and sensitive strains of Fusarium head blight (FHB) pathogens(Fusarium asiaticum and Fusarium graminearum)in Jiangsu,Anhui,Shandong,Henan,Hubei,Hebei and Sichuan provinces,as well as the mycotoxin chemotype and timing analysis of detectable MBC-resistant strains,the diffusion path of MBC-resistant pathogen of FHB from East to North and West of China was studied.The results showed that the dominant pathogenic population of FHB was F.asiaticum in Jiangsu,Anhui,Hubei in Yangtze-Huaihe River Valley and Sichuan province,while it was F.graminearum in Shandong,Henan in Yellow-Huaihe River Valley and Hebei province.However,all MBC-resistant strains detected in Shandong and Henan were F.asiaticum.The mycotoxin chemotypes of MBC-resistant F.asiaticum strains from Jiangsu,Anhui,Shandong and Henan were 3-AcDON and NIV,with 3-AcDON made up most of it.Carbendazim resistance was not detectable in the pathogens in Jiangsu province until the fungicide carbendazim had been used continuously for more than 20 years,while the resistance became detectable in Shandong and Henan provinces in recent years shortly after the intermittent application of carbendazim.Therefore,we speculate that the emergence of carbendazim resistance of FHB pathogen in Shandong and Henan may be diffused from eastern China by the ways of seed transporting and area-cross operation of combine harvester.