I was going to suggest a nitrogen deficiency but seeing that the plant in the background looks good and green it may not be that. As for the tiny spots that reminds me of spider mite damage but checking the underside of those leaves would easily reveal those and their webbing being present. The larger hole damage could be cucumber beetles but those should be easy to find too, esp crawling around inside the blooms. What variety of squash are you growing, summer or winter types?