Cucumber problems

It's not really a good day today! I've several outdoor cucumber plants growing in pots and growbags around the garden - about half long green ridge and half Marketmore. On one of them the leaves feel very brittle and are covered in a white bloom that's difficult to get off. The cucumber next to it (different variety) looks completely unaffected. Is it powery mildew?

Thanks in advance for any help.

K

 

Thank you, was a bit worried I'd have to destry everything, especially as it's spread to the courgettes too.

 

You could give them a spray... your garden centre should have an organic mildew control.