It is some kind of damping-off fungus that probably came from your basement. These funguses will usually die off in the heat and sunlight. In the meantime, trim off the affected leaves. I will usually not trim leaves that are just beginning to get infected if I think I might be pruning back too much -- the plant needs some leaves to photosynthesize. The new growth usually doesn't get infected too much. This is not powdery mildew, which kills cucumbers within a week or so of being visible. Most of your plants should survive without much of a setback. Cucumbers are really finicky though, especially about being cold at all.

Well, wash off what you have on there now. It's not milk AND baking soda--- it's either OR. 1 part milk to 10 parts water. or 1 TB baking soda and 1 tsp insecticidal soap to a gallon of water Here's some more info. Kevin Here is a link that might be useful: Powdery Mildew

Thanks for your hints, MD. Yup, I think this is merely insect damage. However, I find those spots too large to be only from aphids. I am guessing it is a combination of aphids, striped beetles and maybe other critters as well. I have Bug B Gon insecticide from EcoSense. I am trying to keep things organic (although I do think that chemicals are no big deal as long as you really want to care for a plant and they don't damage anything you don't mean to, like the neighbour's crop). It says here that it will control all stages of aphids, spider mites and whitefly, spittle bugs, adult and nymph stages of thrips, flea beetles, caterpillars, mealybugs, scale insects and sugar ants. It contains 0.5% pyrethrin and is lebeled as a skin irritant. Here's the deal. I don't like that it is organic AND pretends to take care of all these bugs. If it were true, then nobody would have harmful bugs anymore, so I am suspicious. Somehow, I am thinking it may be damageable to the plants and may also kill beneficials (I am very lucky to have swarms of ladybugs). Do you think the benefits of using it would outweigh the risks? If I indeed have striped beetle damage, this product wouldn't work. Can I do something against those that can be made at home or that is easily purchased? Also, I have Bug B Gon insecticide soap (supposedly controls aphids, earwigs, mealybugs, spider mites, psyllids, pear and rose slugs [sawfly larvae], soft brown scale and whitefly--the soap 47% potassium salts of fatty acids and is lebeled as a skin and eye irritant), but I still don't understand the difference between insecticide and insecticidal soap. Both are used in the same concentration, applied the same way and at the same frequency, so what is the difference? Which one should I use? Should I use one this week and the other next week and alternate? Also, I think right now would be a good time to spray. It is a bit windy, but otherwise, we have nice cloud cover. There is a risk of rain later on and all through the week. Would spraying these products during a cloudy day (daylight but cool and no sunshine) be a problem? I don't want to miss my chance. Please, help as this is about my first bug challenge and I am pretty much a noob.

Environmental -- sun; bright light; and/or brief water shortage.