I am growing a winter spaghetti squash for the first time. I have grown other cucurbits in the past but I have never seen symptoms quite like this. I've include a picture of a leaf to help with identification. I live in Pennsylvania where summers are very humid.

The symptoms appeared on the largest, oldest leaves first, then slowly continued down the vine to other leaves. The spots seem to start yellow then develop into brown dead spots. The irregular spots seem to be contained by leaf veins. Some of them have fallen out and left holes but the holes seem to be less common.

I removed one entire plant after the infection began spreading down the vine. Unfortunately, the adjacent plant recently started showing the same symptoms. I cannot figure out if it is viral, bacterial, or fungal. I have sprayed them thoroughly with a Neem Oil dilute twice, but it has not stopped the progression.

Any help would be greatly appreciated!!