Effect of application timing of metconazole on Fusarium head blight development and mycotoxin contamination in wheat and barley

The effect of application timing of metconazole on the control of Fusarium head blight (HFB) and mycotoxin accumulation in wheat and barley was investigated. Single and double applications of metconazole at different spray timings were performed in a wheat field trial. In single application plots, the mid-flowering stage was the optimal application timing of metconazole for controlling FHB symptom development, and the milking stage was optimal for reducing mycotoxin contamination. Similar efficacies were observed in all spray timings in double application plots, which included the mid-flowering stage and another spray timing. In the barley field trial, application at the mid-flowering stage controlled both FHB development and mycotoxin contamination with the highest efficacy. Similar efficacies for controlling the development of FHB in the barley field were observed with single and double applications of the fungicide. However, mycotoxin contamination was lower with double application than with single application of the fungicide. (C) Pesticide Science Society of Japan