I suffer terribly from graymould on my cucs and gourds.
There are few chemicals left for home use now but I have tried one (I think it's called Di-thane 947) without success.
In the end I have resorted to diluted Fairy liquid (washing up water to you) which actually kills off the mould. However the plants then take some time to recover.
What I really need is a preventative solution as this problem appears annually. I would of course prefer an organic solution but hey I grow to eat something too. This problem wipes these groups of plant out totally.