Marquette nutrient deficiency?t

[havlikn]

I have found this discoloration on my Marquette leaves, have not noticed any issues on other vines in the area. Only thing I can find in my research is potential potassium deficiency. Any thoughts?

 

[Masbustelo]

I don't know where your located, but weren't there problems with Marquette early on with certain soils in Iowa with too much or to little potassium or phosphorus? Here you go. http://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=3054&context=etd

 

[havlikn]

Interesting article. I am located in se wisconsin. I will have to dive more into the article.