Very serious case of powdery mildew. It looks like that plant is too far gone to ever do well.

Powdery mildew in summer in Louisiana? I think it's bacterial wilt.

Here is a link that might be useful: bacterial wilt

Dig up the roots of one of them. You may find something has been attacking the roots or lower stem. This would weaken the plant enough for molds and mildews to take over. I'd wager you would find an anemic root system on these dying plants.

They are planted in containers if I'm seeing correctly. Hot weather in direct sun, maybe the roots are cooking?? One of the containers looks kinda small, and maybe not getting adequate water? If they are in the EB's in the photo, water should not be an issue but excessive heat to the plants roots could be.

It was said: "Powdery mildew in summer in Louisiana? I think it's bacterial wilt."

Because I don't know anything about bacterial wilt, I'll give you that possibility.

But please look at the leaves, they are coated with PM.

Beyond that, I also saw they are in containers. And I think those comments (above) are right on.

But since the plant is essentially gone, yes, I would remove it (not pull it) and look at the roots. The answer may well be there.

Thanks for the replies.

I'll remove a plant and see what's going on at the root level. I'll report back to what I find.

The cucumber plants are all in an Earthbox. (There are six plants. EB recommends only four, but I figured since these were the bush variety, I could fit more in there).

Oh, and I apologize for the enormous pictures. I thought they would be much smaller than that.

I'll report back.
Thanks for the help.

I dug up a cucumber. I didn't notice anything "off" with the roots. If it was powdery mildew, would something be in the roots?

I can't remember seeing any bugs near the plants. However, it is quite possible.

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Stem shot. I didn't notice any sticky stuff, which is supposed to be an indictator of bacterial wilt.
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It sure looks like powdery mildew on those leaves, and lots of it.

Jim

cucumber beetles

I've looked up cucumber beetles. And Yep, that is most likely the culprit cause I have definitely seem them around.

Now I know how to control things next year.

Thanks for the help everyone.

It's also possible you are having a severe case of mosaic virus but if is the culprit you should be having problems with tomatoes and peppers also . From looking at your photo's that pot your growing in is way to small and those plants have gotten a lot of stress on them. I suggest planting em over you still have pleanty of time. Just plant them elseware and in a differnt larger disinfected container

almax, My cucumbers look just like yours!! Did you ever find out for sure what it was, and how can I prevent this next time? Thanks!

OMG people. Downy mildew. Looks like a pretty classic case. Powdery mildew there too, but I don't think it's what killed 'em