关键词: 小麦, 赤霉病, 杀菌剂, 毒力, 增效组合

Abstract: In order to screen out the fungicide combinations that can effectively control Fusarium head blight and alleviate the resistance of the single fungicide to Fusarium graminearum, the toxicity of 14 common fungicides to Fusarium graminearum was determined by mycelial growth inhibition method, and the fungicide combinations and ratios that can improve the efficiency were screened. The results showed that the EC₅₀ of tebuconazole, diniconazole, difenoconazole, flusilazole, prochloraz and imazal on the mycelial growth of pathogen was 0.106 6~0.905 9 mg/L, and the EC₅₀ of hexaconazole, triazole, propiconazole, propiconazole and pyraclostrobin was 1.423 6~7.664 2 mg/L,which were more sensitive to Fusarium head blight. The EC₅₀ of hymexazol, thiram and seed dressing was 17.343 8, 11.290 1 and 84.518 8 mg/L, respectively, with poor antibacterial activity. The mixture of antifungal and propiconazole with high activity was mixed with 1∶0、0∶1、5∶1、3∶1、1∶1、1∶3、1∶5 and 1∶7（m∶m）, respectively. The joint toxicity test and evaluation results of 1︰3 and 1︰5 showed that the mixture of the two fungicides had obvious synergistic effect on inhibiting the growth of wheat scab, and the co-toxicity coefficients were 269.33 and 417.58, respectively.

Key words: wheat, head blight, fungicides, toxicity, synergistic mixture