Research On The Fungicide Resistance And Management Of The Wheat Scab Fungus Fusarium Graminearum

Fusarium graminearum is the major causal agent of Fusarium head blight (FHB) on wheat. With the long-term use of fungicides recently, commonly used fungicides represented by the carbendazim have been applied for more than 30 years, which causes the increasing fungicide resistance of F. graminearum. To avoid the abuse of chemicals and disease outbreak, this study examined the fungicide resistance of F. Graminearum including carbendazim, tebuconazole, JS399-19 hoping to monitor and forecast the fungicide resistance of F.graminearum. Results of our study demonstrated that:the resistance frequency to carbendazim in Jiangsu Province had reached a high level which is up to 27.4% in 2013. In Henan Province and Anhui Province we also found a few of resistant strains of carbendazim, but no resistant strains in other regions. The resistant strains to tebuconazole and JS399-19 hadn’t been found so far in the field. We found five types of F167Y, E198Q/L/Kand F200Y when detecting resistant mutation to carbendazim. At the same time we noticed that the type of F167Y and E198Q had reached 95% of the whole resistant population. Then we detected the resistance frequency of different types with real time quantitative PCR to guide the disease prevention.In order to analysis the relation between the ratio of infected seeds in the resistant region and the amount of Deoxynivalenol (DON), we utilized wheat samples with different disease degrees as the experimental materials to detect the amount of DON with high efficiency liquid chromatography(HPLC). Results of our study demonstrated that:the higher disease levels or ratio of the infected seeds had a more amount of DON. It was very practical using the ratio of the infected seeds to detect the amount of DON, but with different wheat varieties and different infected levels the error can be large.We also made the inoculation experiment in the field and our results showed that: the recommended dose hadn’t been an effective way to prevent and control wheat fusarium blight when the proportion of resistant strains reached 10% and above. Field efficacy trials indicated that tebuconazole, JS399-19 and some mixtures displayed good effects in the control of wheat fusarium blight.