Evaluation of tebuconazole for the management of Fusarium head blight in China

Abstract

Fusarium head blight (FHB) of wheat is caused by fungal populations belonging to the Fusarium graminearum species complex (FGSC). In this study, tebuconazole (a sterol demethylation inhibitor fungicide, DMI) was evaluated for FHB management in China using in vitro tests and field trials. Although tebuconazole has not been widely used in China, another DMI, triadimefon, has been constantly used to control wheat powdery mildew for more than 20 years. The sensitivity of 56 FGSC isolates collected from 2000 to 2002 and 107 FGSC isolates collected from 2012 to 2013 to tebuconazole were compared. The half-maximal effective concentration (EC50) values of the two groups of isolates ranged from 0.028 to 0.262 mg L−1 and from 0.045 to 0.497 mg L−1, respectively, and statistically significant differences (P < 0.05) were found between them. During the 13 years, the EC50 values for tebuconazole increased by a factor of 1.53. In 2012 and 2013 field trials, the control efficacy of tebuconazole was evaluated in fields where triadimefon had been constantly used for over 20 years. Tebuconazole at 125.00 g a.i. ha−1 decreased disease severity by 81.80 and 70.54 %, respectively, reduced the deoxynivalenol (DON) contents by 78.85 and 38.43 %, respectively, and the yield losses were much lower in both years. Therefore, despite the significant decrease in the sensitivity of in vitro tests, tebuconazole was still very effective in inhibiting FHB and DON, and accordingly in reducing yield losses. It can be used as an effective fungicide for the control of FHB of wheat in China.