Yep, chlorosis is beginning. It is a little too early to tell exactly what is missing. It is either nitrogen or iron or magnesium or all of the above. When and what did you fertilize with and how much?
No wonder they are chlorotic. Here is what I would do to all of your plants. First I would trash the langbeinite or use it very sparingly as a soil amendment IF needed. Then I would give all the plants a jump start by giving each plant about 2 tablespoons of bloodmeal and water it in lightly. Then I would treat the plants with Chelated Iron as per directions but mix it with molasses @ 2 oz per gallon of water and water it in lightly. Then I would get some manure based organic granulated fertilizer and put about 2 big handfulls around each plant out to the dripline and water this in heavily. But before you do anything take pictures the day you do all of this and then take the same pictures 7 - 10 days later so you can see the dramatic results.
Food grade molasses is a LOT more expensive than horticultural or feed grade. You will be using quite a bit of it. I pay $12 per gallon. Any organic fertilizer is good as long as it has OMRI somewhere on the bag. Go to a feed store and talk to them. If they don't carry it they can get it very easily. Myself, I use Medina 3-2-3 Growing Green but that is only because it is locally made. There are many others. Just google organic fertilizers
Today I will go check to see if there's any other damage anywhere in my garden and see what you think it is. Mainly ive noticed there are some little chewing holes in leaves here and there.
Yes, spinosad. If you saw one cucumber beetle there are or will be more. Spray everything.
