Abstract: A prime mover has a programmable control system for applying a material, such as a liquid herbicide onto programmed locations in an agricultural field, by creating a program manually on an initial pass of the field in relation to the position of the prime mover, and storing the information in a program for subsequent control in subsequent passes of the prime mover for repeating operations. A microprocessor having a programmable memory is utilized with manual controls for operating a sprayer when weeds are visible, and then correlating the position of the prime mover and the operation to be performed in a subsequent operation and permitting the memory to control the on and off applications of the sprayer. The unit makes use of low cost microprocessors with programmable memories and permits a low cost repeatable operation merely by providing a reference starting position, and a known path in which to travel.