grape vines

[dawsson]

We have two seedless grape vines in an unheated greenhouse which were planted 18 months ago.
Last year both vines grew strongly and one of them continues to do so, bearing fruiting bunches for the first time this Spring.
The other last Autumn was attacked by a dark grey mould which killed off several of the laterals. We treated the greenhouse with a sulphur candle, and this seemed to do the trick. The one vine continues to grow strongly with no defects, the other whilst initially growing strongly this year ( and bearing fruit bunches) is showing signs of a resurgance of the mould growth.
Any ideas on the appropriate treatment?