Brown spots with holes on Zucchini Leaves

I just noticed yesterday these brown spots with holes on my Zucchini plants -- all three of them.  They weren't there the day before I believe.

Is this due to magnesium deficiency?  Should I go buy some epsom salt and water some in?

I haven't augmented my beds with magnesium.   Just Jobe's Organics Vegetable and Tomato Fertilizer 2-5-3.  I haven't done any green sand, azomite nor kelp as well.

Hi Jennifer, I think the spots on your zucchini leaves are from anthracnose, a fungal disease, and not a mineral deficiency.

Doesn't look like a magnesium deficiency to me.