On 24/08/2011 09:26, Moonraker wrote:
I have three outdoor courgettes plants doing well to date. However the
last couple of days a lot of the older leaves are covered in a white
substance. Is this mildew, if so will it harm the plants and what steps
should I take to eliminate it?

Probably. Not really worth the effort of doing anything provided the
plant is still growing vigorously (which they do at this time of year).

Mine always get a bit on older leaves but it doesn't affect cropping.

Regards,
Martin Brown