A mower deck for a rotary vegetation cutting mower device pulled by a motor vehicle includes a housing defining a main portion disposed generally horizontally when the mower deck is in a position for cutting the vegetation and a pair of side walls extending downwardly from the main portion generally perpendicular thereto and forming in combination with the main portion a compartment of the housing wherein the blade rotates. At least one of at least one reinforcing rib and raised portion is disposed on the top surface of the main portion. A plate is releaseably secured to the top surface of the housing and carries a gearbox thereon. The housing and the plate are manufactured from a polypropylene material having a thickness of about one inch.
