Thank you for your reply. I am in San Francisco. These flies also attacked my tomato plants. I can see that it damages plants, but having hard time getting rid of them. I already tried watering with mosquito bites, covered soil with Diatomaceous Earth, placed sticky cards in all containers. Also, placed vinegar with soap plates around plants. I also tried to spray with insecticidal soap and with Bonide Neem Oil. It seems like this little creatures are invincible. I am out of ideas what else can be done. I hoped that if I can identify them I can find right thing to get rid of them. I would really appreciate any suggestions. I am adding picture with insect on tomatoe leave to shoe actual size. They are tiny, flying and jumping. They like to sit on top of the soil and jump on window when sun rises. As you can see tomatoe leaves are not looking good.

When I had it, that's how it looked to me, but it can take different forms, I guess. I assume your spots are powdery, and can be dusted off if rubbed.

I too never prune cukes but there is a lot of wisdom out there that says that you should. The idea, it is said, is to balance vine growth and fruiting. The presumption, I guess, is that cukes waste too much effort on leaves and do not spend enough effort on fruit. One can argue with this in a very basic way. The main purpose in life of a plant is making new seeds. Those seeds are within the fruit. Fruiting plants have evolved to optimize the amount of seeds and fruit produced without anyone stepping in to do pruning. I guess if you're doing some unusual kind of fertilization, that optimization may not be right. So if you do it, make sure you really understand WHY you're doing it. If your cucumbers are climbing, then strategic pruning can help them grow in the right direction. If they're just getting messy, pruning can neaten them up. Pruning can help with ventilation, which can cut down on fungal infections. Also, it's often a good idea to prune early flowers, to encourage fruiting on a more mature plant. In all fairness, a plant doesn't know if it will even live to be mature, so it tries to pump out fruit a little before it might be most ready. Curiously, I don't hear anyone telling us that we need to prune squash, so why one cucumis should need pruning but another doesn't has to be considered a little mysterious.

Many years ago, I just couldn't grow regular cucumbers anymore. The cucumber beetles killed everything off. I discovered County Fair cucumbers. They apparently don't have the bitter gene, which is what attracts the beetles. I immediately could grow cucumbers again. I was so happy! I've grown this variety for probably 20 years and never had a problem again. Well, they're back this year. I bought County Fair from Jung seeds and wrote to them, saying that I wasn't sure these were County Fair seeds. Their staff horticulturalist wrote back a nice long letter, explaining lots of stuff I didn't completely understand, but said that I was just lucky to not have had any cucumber beetles for so long. I find that hard to believe, when I immediately, and for many years afterwards had no beetles. He did mention climate change, which can upset things now. We were in a moderate drought, and maybe they just got desperately thirsty? I don't know. I just find it strange that they're attracted to my cucumber plants now. They're eating the leaves and also causing wilt. Any ideas? Anyone have this problem with Jung See County Fair cucumbers this year? Thanks!