Stylet-Oil is used to control certain fungal diseases (such as powdery mildew, Botrytis bunch rot and rust). Stylet-Oil is an excellent eradicant and will kill powdery mildew on contact as well as prevent development for 10 to 14 days depending on the use rate. Stylet-Oil is successfully used in grape powdery mildew control programs throughout the world, including some of the premiere wine grape growing regions in California, Oregon, Washington and New York.