Studies on the control of Fusarium head blight of barley and wheat and mycotoxin levels in grains based on time of infection and toxin accumulation

Abstract

Fusarium head blight (FHB) caused by several Fusarium species, especially the F. graminearum species complex, once considered a single species [F. graminearum Schwabe, teleomorph: Gibberella zeae (Schwein.) Petch], is a widespread and destructive disease of wheat, barley, and other small-grain cereals. These pathogens infect spikes and reduce grain yield and quality. Moreover, the FHB pathogens produce mycotoxins such as deoxynivalenol (DON) and nivalenol (NIV), which are toxic to humans and other animals. The Japanese government established provisional guidelines for DON content in unpolished wheat grains as 1.1 mg/kg in 2002, and accordingly, an effective control strategy to reduce the risk of mycotoxin contamination in wheat and barley has been strongly needed. In this study, we studied the time of mycotoxin accumulation in developing barley and wheat grains, and on the basis of our findings and on additional field experiments, we determined the optimal timing of fungicide application to effectively reduce mycotoxin levels in barley and wheat. Studies on barley