Paper-Thin Brown Spots on Laurentii
I bought this Laurentii last September at the local giant home store (think Home Depot, but bigger, and Japanese). I don't water it much, it's got a ridiculous amount of gravel in the bottom of the (very tall) pot, so it drains out reasonably well. It's been doing well! The occasional brown spot or edge, but my mother's sansevieria always had a few leaves like that, so I didn't worry.
But recently, on a couple of previously healthy leaves, these really big brown spots have appeared. They're paper thin, completely dry, entirely different from the aforementioned 'normal' ones.
There's also black dots in them. I assume this is a pest of some manner? Any suggestions you can give would be appreciated. Thanks.