Rocket - pest/disease?

[ee909]

Hi,
I am growing rocket for the first time, I have about 10 plants and have been having a good crop from them. However, in hte last day or two all the leaves on the plants have become covered in what appear to be white spots. On closer inspection the white spots are actually see-through. Does anyone have any ideas what is causing this? Can I stop it and can I still eat the leaves??!

Thanks for any advice,

E

[Cabbagelover]

Splashing the leaves with water when you are watering can lead to infections and downy mildew.