60s or 70s Suspence Thriller

I saw this movie years ago. I remember only fragments. There was a middle aged woman trying to kill a young, attractive woman.

At the end they were on a farm and the girl was hiding in a cellar like the one in the Wizard of Oz. The scary lady had a pitchfork and she was standing outside the cellar leaning on it as the girl hid there.
That’s about all I’ve got. What movie is that? Thank you.

PS the lady was heavy set and large in general and the girl had long, straight hair.