Last year, my first garden, I put my cucumbers on a trellis. This year, planting less and having more room, I let them go on the ground.
Approximately 11 of the last 16 days have been on average about 8 degrees below normal. It's been generally in the mid 70's. Even had a couple of days in the upper 60's. A good bit cooler than our average 84 this time of year.
On one cucumber I did see 3 small bumps that looked like the beginning of the scab picture I saw on the net, and thought it might be the early stages of scab. It's seems hard to determine disease's because they can look different on different plants.
From fairly early on, when the vines were only 2 or 3 feet long, I've had some leaves get first yellow areas, then tan, then the tan may become holes and the edges of the leaves would curl a little and turn brown. They would end up a raggedy looking mostly tan leaf with holes in them. But this was mainly in the center of the plants and the new outer leaves looked good, and I had loads of good cucumbers.
I was just outside looking, and the leaves with yellow spots is advancing. Getting near the outside of the plants in one area.
I've also had leaves that are under the 'canopy' turn pail yellow and die. I figured that was normal. They didn't really seem to be diseased.