Combination of Bacillus velezensis EA19 and Carbendazim to Control Fusarium Head Blight on Wheat

WANG Wenxiao; LIU Meiling; QUE Yawei; ZHENG Lei; ZHANG Qiang; YU Dazhao; YANG Lijun; GONG Shuangjun; ZENG Fansong; LI Li

doi:10.15933/j.cnki.1004-3268.2024.10.013

Abstract：In order to determine the controlling efficacy of Bacillus velezensis EA19 combined with chemical agents on Fusarium head blight(FHB),the optimal combination ratio was determined by the mycelium growth rate method,plate colony counting method and Horsfall method,and then verified by detached wheat spikes inoculation tests and field trials.The results showed that the inhibition rates of spray powder and freeze-dried powder of EA19 fermentation broth on the mycelial growth of Fusarium graminearum and F.asiaticum at different concentration were 22.53%—93.96%,and the EC50 values were in the range of 5.794 4-10.916 4 cfu/mL.The strain EA19 had good biocompatibility with 25-100 µg/mL carbendazim,but not with 25-100 µg/mL prochloraz and tebuconazole.When carbendazim was combined with spray powder or freeze-dried powder of EA19 at the volume ratio of 6∶4,7∶3 and 8∶2,the co-toxicity to F.graminearum and F.asiaticum was the highest,and the greatest toxicity ratio was 1.15-1.36 in these ratios.The control efficacy on FHB of detached wheat spikes by the combination of carbendazim and two types of EA19 powder with a concentration of EC50 in different volume ratios was 47.91%—73.50%.In field trials,when treated with the combination of EA19 freeze-dried powder with 30%reduced carbendazim,the control efficacy(53.76%),deoxynivalenol toxin content in wheat grains(0.50 mg/kg),and theoretical wheat yield(5 994.35 kg/ha)were not significantly different from those treated with full dosage of carbendazim.In conclusion,B.velezensis EA19 and carbendazim have synergistic effect in the control of FHB,and their combination can reduce the dosage of carbendazim.