The message
from "david" contains these words:

I found the question, and the RHS link, most useful. I have a 5 or 6
year-old chasselas white vine growing outdoors here (W Brittany) which I am
maybe guilty of having overcropped. Whatever, this year the central section
(i.e. the section of oldest wood, and closest to the stem) has many dark and
shrivelled grapes, and is losing its leaves pretty quickly at present. The
other sections, which flowered a little later, and fairly normal. I have
suspected cold damage to the earliest fruit, but now wonder whether I
haven't been pruning and cropping too much, compounding the problem.

You can't really prune a vine too much, unless you start removing the
main part. When the leaves have dropped, prune off all the laterals
*LEAVING TWO BUDS*.

When the fruit has set you can get the secateurs out again and remove
all the laterals without fruit, and prune off the ends of the fruiting
laterals leaving three or four leaves beyond the bunch.

Do not do this second pruning too early as the cuts will bleed, and that
may well kill the vine.

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Rusty http://www.users.zetnet.co.uk/hi-fi/tqt.htm
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