Impact of epoxiconazole on Fusarium head blight control, grain yield and deoxynivalenol accumulation in wheat

Fusarium head blight (FHB) is a destructive disease of small grain cereals withFusarium graminearumas one ofthe most important causal agents. FHB not only can reduce yield and quality of grains, but also lead to accu-mulation of mycotoxins in grain, thereby threatening human and animal health. In this study, we observed thatepoxiconazole exhibits strong inhibitory effects on both carbendazim-resistant and phenamacril-resistant iso-lates using mycelial growth inhibition assays. The artificially inoculatedfield trials further showed that epox-iconazole increased the control efficacy of FHB by being able to control carbendazim-resistant and phenamacril-resistant isolates. Epoxiconazole triggered DON production andTri5expressionin vitro. However, in addition toincreased FHB control efficacy and grain yield, decreased DON levels were measured infield trials after epox-iconazole applications. FHB control, grain yields and DON levels were significantly correlated with each other,suggesting that the visual disease rating can be used as an indicator of grain yields and mycotoxin con-tamination. Meanwhile, the frequency of carbendazim-resistant alleles inF. graminearumpopulations was dra-matically reduced after epoxiconazole applications. In addition, epoxiconazole seed treatments had no effect onseed germination but phytotoxicity was apparent through growth inhibition of wheat seedlings. Overall, thesefindings of this study provide useful information for wheat protection programs against toxigenic fungi re-sponsible for FHB and the consequent mycotoxin accumulation in grains