Powdery Mildew on Strawbs. Help

[Goldengirl]

Hi.
I've just been out into the garden and discovered my strawberry plants are covered in what I think is Powdery Mildew. I am gutted, I have 30 plants in a large starwberry planter all with green strawberries on at the moment. Will they all be ruined? Is there anything I can do to get rid of it? This is my first year growing starwberries and was really looking forward to tasting my first one in a few weeks. Can anyone tell me what I can do? Thanks

[FB.]

Any chance of a picture?

Which variety are you growing? - Some varieties of strawberry are much more prone to disease than others.