Anyways, I've been playing this mod a while, and today on my server, I took a visit to my soul-forged steel beacon and I noticed that there was this weird puke-green stuff growing on the grass. I picked it up with with the block dispenser and it said "Blight." I looked it up and it's not a feature of vanilla Minecraft, and it isn't anywhere on the Better than Wolves Wiki or Forum. I am on BTW 5.54.
I understand it is a plant disease of some sort but:
What is it?
What can it be used for?
And when was it implemented?
Edit: this is what it looks like: