using sulfur on marquette grapes

[wood1954]

Has anyone had experience using sulfur on Marquette grapes for powdery mildew control? I have seen contradictory evidence that is harmless or it could be harmful.

 

[mfzona]

I use it every spray with captan or mancozeb. Works wonderfully and had no issues.

 

[wood1954]

great news thanks

 

[wood1954]

It seems my Marquette get leaf burn from sulfur.

 

[Cynewulf]

Sorry to hear that. Like mfzona I mix it with either mancozeb or captan and immunox and haven’t had any problems on my Marquette. I think you do have to be careful on the volume of water you mix it with, the the outside temperature, and avoid applying it in conjunction with any oils such as neem oil. I specifically chose Marquette because I wanted to be able to spray sulfur in my vineyard and the other hybrids that are more common in Virginia were sensitive to it. So far it hasn’t been a problem.

 

[wood1954]

So far , I seem to spray a day before it gets up to 90 degrees or so, I wonder if the heat and humidity have something to do with it.

 

[wood1954]

I figured it out , the problem was me. I’ve been spraying Phostrol at a rate 10 times recommended. I must have missed a decimal point When I was determining the proper rate.

 

[Cynewulf]

Ouch, glad you figured it out. I don’t use phosphorous acid (instead mancozeb then captan for downy mildew) but understand you have to be careful with the concentration and avoid spraying it too frequently or deal with toxicity: Top Mistakes of New Grape Growers. Hope it’s smoother sailing from here on out!

 

[Ct Winemaker]

Double A says Marquette are sensitive to sulfur. I use it on my other vines but haven’t on the Marquette. It sure would be a lot easier if I could spray them the same as the other vines. Interesting that you folks aren’t having a problem with it - good news.

 

[wood1954]

Cynewulf, thanks for the link, good info