On Thu, 30 Jul 2015 18:44:35 Chris wrote:

Grapes have just got grey mould in last two days.
Always been trouble free in previous years.
South facing brick house wall.
Boskoop Glory black eating grape.
All fungicides seem to be withdrawn from sale.
(But please tell me if you know different.)
Any possible action to take?

If it is just on the grapes then it is almost certainly botrytis. Remove
all infected grapes otherwise it will spread. This usually occurs in
warm weather when there has been rain for a long period.

If, however, you find pale patches on the upper side of leaves as well
and underneath there are white patches of mould then you have downy
mildew. This is more serious as, once it has taken hold, then you are
likely to lose the whole crop.

If you have a powdery film all over the leaves then you have powdery
mildew. Treat as for downy mildew.

Vines should be sprayed with bordeaux mixture (and dithane for powdery
mildew if you can still get it) once every two to three weeks from May
onwards until about three weeks before the grapes are ripe, even though
you may not see any evidence of mould. Once you can see it, it's usually
too late, as I know to my cost.

David

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David Rance writing from Caversham, Reading, UK