Abstract: A defoliator for detopping sugar beets and the like includes at least one laterally extending rotor on which a plurality of flails are mounted. The flails are of polyurethane and have a hub at one end provided with a bore so that they can be pivotally attached to a rod supported on the rotor. Each group of flails includes tapered flails at the ends of the group and rectangularly configured flails therebetween with still an additional tapered flail between the two non-tapered flails. Each flail has a rigid cutting member at the free end thereof, each cutting member being channel-shaped so as to provide parallel flanges projecting in one direction with respect to an integral web having a hole therein so that the member can be bolted to the free end of the flail with which it is to be associated. Each cutting member has an additional flange extending in an opposite direction from the parallel flanges, the additional flange residing in a proximal relation with one side of the flail.