The present invention provides an apparatus for spreading on the ground granular and liquid treatment materials at the selection of the operator. The apparatus includes a motorized cart having granular and liquid storage compartments and associated controls to release the treatment materials on an as needed basis. A spray wand is also provided to permit spraying the liquid material for detail applications. A pump is operably connected to the liquid storage compartment, the spray wand, and one or more area spray nozzles to provide the liquid for spraying purposes. The granular material can be radially broadcast from the granular storage compartment as the cart traverses the ground. Controls for the motor and the granular and liquid treatment operation are mounted to the apparatus for easy access by the operator. The present invention also provides a retrofit package for inclusion on available granular spreaders to provide the motorized granular and liquid treatment apparatus disclosed herein.