A row unit (14) of a corn head assembly (10) for an agricultural harvester capable of reducing grain loss is provided. The row unit (14) includes a frame (22) and first and second spaced apart row unit arms (24, 26) mounted to the frame (22), and a top plate (44). The top plate (44) is positioned about a rear end of the frame (22) and includes an outer surface (48) having a retaining structure (58) configured to inhibit a flow of grain in a forward direction along the outer surface (48).
