Mint with black areas and some foam

[Josephny]

Does anyone know what happened to my mint plants?

They have some black areas on some leaves, and a couple of areas with a foamy glob.

Are they safe to eat?

 

[Oliver Buckle]

My guess is that if you look in the foamy glob you will find a froghopper, a little grub that makes the foam to protect itself and sucks juice from the leaves, but I am on another continent, so maybe something different. I don't know about the black spots, possibly fungal?. My guess is it would be fine to eat, but I don't know, and I would be tempted to cut it right down hard and give it a good water so you get some fresh, uninfected growth.
Unusual, mint is usually pretty bomb proof.

 

[cpp gardener]

The foam is a froghopper, although here we call them spittlebugs. You can wash them off with plain water from a hose. The black spots are a bacterial infection. There are several organic controls available.