There's a fungus among us.

See that white powdery nonsense on the sad leaves?  That would be a moldy, nasty fungus.  I'll be spraying it with a vegetable-friendly fungicide, but I already had to pull up one of my zucchinis because it had such a bad fungal infection.

This kind of fungus can occur when it rains a lot and the leaves get wet in a humid environment.  The humidity prevents the leaves from drying out and hairy leaves like pumpkin, zucchini, and cucumber get moldy and then die.   Heavy rains followed by humidity?  Why, you just described Maryland's climate to the T.

Stay dry,

Christine