MilStop is an EPA-registered, broad-spectrum foliar fungicide for curative control of powdery mildew and preventative control of many other foliar diseases. MilStop has a 1-hour REI and is compatible with many beneficial insects. The active ingredient in MilStop – Potassium Bicarbonate – has been approved by the Food and Drug Administration as a G.R.A.S. (Generally Regarded as Safe) product.