As you know, GreenCure is available on line for a price. A search for potassium bicarbonate, which is the same as the GreenCure product, brings up several companies selling it much cheaper; a pound for under $10.00. As a spray mix I would use three tablespoons per gallon of potassium bicarbonate plus 1/2 teaspoon of a sticker such as my favorite, Method Go-Naked organic dishwashing liquid available at Target stores.

Thanks Nandina - I know the extension folks say that it's virtually impossible to control Entomosporium around here. Have you had any luck fighting off that stuff?