thanks for the help everyone! the bags are on cardboard, (it looks like concrete in the photos) so its not hot to walk on,(great weed control) i have grown cukes like this with much sucsess, in the past. they are in full sun, the problem may have cropped up after several days of rain? I will use a fungicide and clear out most of the affected leaves,,, per the advice. i also recently turned the watering cycles on every day for 10 min with a drip irrigation,, the drip heads on the cukes are 1/2 gallon per hour)(,before that it was every other day ,,,but the plants were wilting under the sun, after increasing the watering the wilting went away. i do have alot of drainage holes poked in the bottoms of the bags,,,,, maybe over watering?? like waqs suggested above maybe powdery wilt ,, after some fungicide ,, aplication we shall see. and i will post results Thanks again everyone!!!