Hi all- this is my first time growing zucchini. I have them in a large container. This past week I noticed the yellowing leaves & one or 2 have a white spots. I don’t see any insects or flys. What should I do ? There are a few zucchini almost ready to pick and I’d like to keep this plant going through the summer(lots of flowers still). I added the basil plant - next container over. The leaves are getting holes in the middle of the leaves - same thing as I cannot see anything eating them. I will take any advice!! Thank you in advance.