Abstract
Fusarium head blight (FHB) and deoxynivalenol (DON) contamination have been great concern in wheat production in Hokkaido since a guideline level for DON was established. Chemical control is one of the effective measures to reduce FHB and DON levels. We recommend following five fungicides: tebuconazole, propiconazole, kresoxim-methyl, iminoctadine-acetate, and thiofanate-methyl. These fungicides reduce both FHB and DON levels. As the timing of fungicide application is decisive to reduce FHB level, the first application should be started at beginning of flowering. The frequency of fungicide application is also important especially for DON control. Three and four applications at one-week intervals are recommended for winter wheat and spring wheat, respectively. These recommendations have so far been approved by wheat growers and reduced both FHB and DON levels practically. However, wheat grower's demand for reducing application frequency is increasing. Further investigations are required to establish the control by fewer fungicide applications.
