As grape growers know, vineyards have common primary diseases, such as powdery mildew, botrytis and sour rot in the western US and downy mildew, black rot and Phomopsis in the eastern US. Many growers prefer to moderate the use of pesticides, or to be organic or sustainable. Modern thought is that we don’t want to use a lot of pesticides if we don’t need to. We want to find a ...