Inhibitory Effects of Phenamacril, Tebuconazole and Their Mixtures on Fusarium graminearum in Wheat

摘要

Fusarium head blight caused by Fusarium graminearum is one of the most serious diseases in wheat production worldwide, which serious- ly affects the yield and quality of wheat. Wheat grains carrying the pathogen are poisonous to human and livestock health. With the long-term use of single chemical pesticide, the drug-resistance of F. graminearum is increasing day by day, and mixed agent is one of the effective strategies to im- prove the efficacy and delay the resistance. The mycelial growth rate method was used to determine the inhibition rates of phenamacril, tebuconazole and their mixtures (1:1, 1:3, 1:5, 1:7, 3:1, 5:1 and 7:1). The synergistic coefficient (SR) was calculated by Wadley method, and the combined action types of the two agents were evaluated. The results showed that the EC50 of tebuconazole was 0.418 28 mg/L, and that of phenamacril was 0.489 8 mg/L;the optimum mixture ratio of phenamacril and tebuconazole was 1:1, with the EC50 value of 0.053 74 and the synergistic coefficient of 4.269 6, and the control effect of mixed agent was significantly better than that of single agent. It is feasible to control Fusarium head blight by mixing phenamacril and tebuconazole, providing a theoretical basis for development of new compound agents and effective control of Fusarium head blight.