A vine crop, e.g. tomato harvester is disclosed which has a crop processing mechanism that is movable through a field and a rearwardly and upwardly inclined elevator or header that is pivotally connected to a forward end of the processing mechanism. A leading edge of the elevator is proximate the ground and a level control wheel is vertically movably connected to the header and positioned forward of its leading edge. The wheel is defined by a multiplicity of tines, the free ends of which engage the ground so that the wheel rolls over the ground as the harvester moves through the field. The tines have a longitudinally convex configuration facing in the direction of rotation of the wheel. A control mechanism is actuated by relative vertical movements of the wheel for raising and lowering the leading edge of the elevator in response to ground surface irregularities sensed by the wheel.