I am growing three varieties of grape at the present time. Sabre vois, Frontenac and St. Crois the picture shows the leaf off of one of my St.Crois vines. I have never seen this before and it is only appearing sporadically in the St.Crois nowhere else. any thoughts? Thanks Larry
This looks like low K, but symptoms for grapevine leaf roll virus are very similar (it interferes with potassium uptake). On a given shoot leaf roll will show on the lower leaves while low K will show on the higher (more recent) leaves. I would suggest you test for both. Ralph
