Jeff,

If the burn is only at the tip of the leaf I would suspect your
fungicide spray was mixed too strong. The spray has a tendency to
flow down to the end of the leaf and if it is too concentrated , will
burn the tip. I also think it's too early for potassium deficiency to
show but I don't know where you live. Also, if it is potassium
deficiency, mulching the vine after giving it ALOT of water will help
the roots absorb the potassium out of the soil. THe vine like all
plants needs moisture to get the nutrients out of the soil. It's why
potassium deficiency is more likely on sandy soils. I have basically
eliminated any potassium defifiency symptoms from my vineyard just by
making sure I mulched the area of the vineyard that was driest which
also coincided with P symptoms. I didn't use any P fertilizer or
ashes.

Hope this helps.

Bob

"Jeff Chorniak" > wrote in message . rogers.com>...
> On some of my largest, older cab franc leaves (basal), I am noticing what
> appears to be a slight burning on the tips of the leaves. Otherwise the
> leaves look good. Good color. Good size, etc.
>
> Any ideas to suggest what might cause this? A deficiency of some sort?
> "General Viticulture" has a paragraph that suggests high sodium, but I'm not
> sure how that would happen.
>
> Regards
> Jeff Chorniak