Emerald fungicide works differently than anything else you've seen used to control dollar spot. That means Emerald can effectively control dollar spot that has developed resistance to other fungicides. When used as directed, Emerald: Provides unprecedented dollar spot control in virtually every major turf species, and in every region, of the United States.Controls dollar spot for up to 28 days with a single application. Delivers better dollar spot control in bentgrass than other fungicides. Gives superintedents a true resistance-management tool. Utilizes low use rates and provides strong residual control.