A scraper employs a support arm for mounting to a frame of an agricultural implement and a frustoconically bowl-shaped scraper member rotatably supported on the support arm in a position facing the open end of the bowl toward a ground-engaging wheel or disc. The scraper member includes a sharpened edge for improved cleaning action and uses a flanged bearing on a closed flat end of the frustoconical bowl for optimal rotational action. Different embodiment disclose unique mounting arrangements, including embodiments with a single sole support arm for ease of assembly, using bends, twists or combinations thereof to achieve suitable positioning of the scraper without additional support pieces, and including other multi-piece embodiments with multiple points of adjustability to allow optimal placement and adjustment of the scraper.