A cornhead row unit including first and second longitudinally extending stripper plates mounted on a frame and having opposed stripping edges which define a gap between them. The frame further includes an adjusting arrangement operatively connecting the frame and at least one of the first and second stripper plates to selectably and transversely move at least one of the first stripper plate and second stripper plate with respect to the other stripper plate to vary the width of the gap. A loss detection device is operatively connected to the frame for permitting measurement of corn kernels lost as a result of drawing corn stalks through the gap to separate corn ears from the stalks.