Objective To study the activities of enantiomers of three triazole fungicides against Fusarium spp..
Method Three chiral fungicides included tebuconazole, myclobutanil and difenoconazole. The activities of fungicide enantiomers against F. moniliforme, F. proliferatum and F. graminearum were assessed by mycelial growth rate method, respectively. The EC50 values of enantiomers were analyzed.
Result The activities of different enantiomers against three kinds of Fusarium spp. were different. The activity of (–)-tebuconazole was higher than (+)-tebuconazole, and the EC50 difference of two enantiomers was 32–208 times. The inhibitory activity of (+)-myclobutanil was higher than (–)-myclobutanil, and the EC50 difference of two enantiomers was 1.4–6.4 times. (2R,4R)-difenoconazole showed the maximum activity among four enantiomers of difenoconazole, and the EC50 difference of four enantiomers was 3.7–15.5 times.
Conclusion For Fusarium spp., the activities of three fungicides show selective difference. (–)-tebuconazole, (+)-myclobutanil and (2R,4R)-difenoconazole show higher activities. These results might contribute to screening higher active fungicides and reducing the use of pesticides.