I have 4 grapevines in my greenhouse, 2 of which seem to have problems. One of them with broad leaves, have bumps on them (approx. 1/4" in dia) with a white powdery substance on the underside of the leaf. The other grapevine, with smaller denser leaves, have a powdery substance all over the underside of some leaves and traces on top of them. I have a product named Garden Fungucide, by Green Earth. Is this good enough, or do I need to spray copper sulfate? Thanks, Mike Port Coquitlam, BC
