I have decided to give up growing pinot noir wine grapes. I've had terrible infestations of powdery mildew for three years in a row. This happened despite regular, weekly spraying with sulfur/copper fungicides. I got some Baco Noir, Chanbourcin and Marchel Foch scions at the spring scion exchange. I am reasonably certain that these hybrid varieties are productive and less susceptible to powdery mildew. But, before I go ahead and rip out my 30 pinot noir vines, I thought I'd check to see if I might be about to make an irreversible mistake.
Any feedback is very welcome.
Thank You,

Mike

I have heard about people using a diluted milk solution (!) as an effective preventer of powdery mildew. Yes, I know it sounds strange, but it's true.

If you are interested, I can probably dig up the info on that.

I haven't tried it because I grow the American labrusca grapes and they don't have that problem, at least here.
John S
PDX OR

Thanks John

I've also read that a milk solution can prevent powdery mildew. As I recall there was a pretty reasonable sounding science based explanation for this.

From what I've read and from my own experience, powdery mildew hates water. It thrives under dry conditions and when simply sprayed with water it dissipates. With the severe drought I've been experience in central Ohio this summer I've had powdery mildew on one of my apple trees multiple times. All I've had to do is spray the powder off with water in the morning before it gets hot and sunny.