In the US and most of the New World, spraying copper sulfate is not a required vineyard treatment. In Europe it is, and it's used during the vegetative growth cycle in rainy periods to combat Downy Mildew, a fungus that, like the global problem of Powdery Mildew, feasts on the plant’s chlorophyll. Downy Mildew is transported by water, so if...[ read more ]