Cucumber beetles [first wave] often first show up when cucurbit seedlings are very small. [Always be on watch for this]. These can be deadly in a day or two to the small seedlings. Sevin will protect them until it rains very much. Whether your plants are saveable is a guess. Some probanly will survive if not earen up too badly. The beetles will feed and then lay eggs in the soil around the seedlings. The larva will eat on roots. A second generation of beetles may not show up for a while.

I think they are called cucumber beetles. The adults eat holes in the leafs and leave them skelatized(sp?). The larvae are in the soil and feed on the roots and spread cucumber bacterial wilt which will kill your cucumbers. I know that rotenone works and NEEM oil is supposed to work on them. The downside to rotenone is that it kills the beneficials and the bees which pollinate cukes. The NEEM oil is supposed to not have this downside. I haven't tried it yet but will be doing it soon becuase I have noticed some chewing on my cuke leaves. I know that there are various companion planting/alternative fixes out there, but I haven't had much luck with any of those. The last two years I have had a much reduced crop becuase of the wilt and so this year I am going to try the NEEM. If you do a general search for cucumber beetle, there are lots of websites with pictures to make sure that is what you have.

Is it wilt or are the stems near the ground cut partially through. The white on the one leaf looks like sun damage. The other plants look like cutworm damage. Take aluminum foil and wrap the stems with a inch to 1 1/2 inch strips. Not saying the perlite does not work but I have seen cutworms on sharp gravel.

If what you have is really BW then the pathogenic bacteria is systemic and in the fruit as well. I wouldn't eat them but it is your choice. If you have researched BW then you know there is an easy test you can do to determine if that is really what it is. Squash plants can be affected by it but the odds heavily favor one of the more common squash problems instead. If either plant recovers after watering or when "out of the sun" then it isn't BW. Dave