See attached photo lower right for a strange growth on a Frontenac grapevine...
See attached photo lower right for a strange growth on a Frontenac grapevine that I am training to an overhead trellis Any idea what this is and should I cut it off? Also any idea why the Frontenac leaves are turning yellow while the grapes appear to be fine
Portage County Ohio
Hi There, The strange growth may be caused by an insect. I would just cut it off since it is a rare occurance. The yellowing on the leave may be magnesium deficiency, if it is on older leaves. I would apply magnesium sulfate. It could be iron deficiency, if the yellowing is on newer or young leaves. I would apply iron sulfate. Hope this helps.