This is hardly the first time this world has experienced a pest invasion. If the natives don't have one, there's certainly some moonblessed from a harsher world you can ask.

[ Midorima heads to the nurse's station to let them know they're leaving, though he simply gives them their names and states that they're checking out. It's only polite to at least notify them, even if he's not sticking around to do Eichi's paperwork. They can mail it to him. He's already done his. ]

You purchased magic?

[ It's not like he knows what he's looking for, as far as he knows Eichi got electrocuted by the vine plant. ]