Abstract: An apparatus and method for the controlled, intermittent, automatic dispensing of atomized fluid, such as an insecticide, into a use area, such as a barn, characterized in that the apparatus and its method of use are controlled to dispense fluid approved for use in the particular use area and supplied from an approved container provided with a vented fluid outlet and dispenser having a code cooperating with a code of a fluid inlet and dispenser means associated with the apparatus. The code includes mating key chambers and key pins arranged in a selected code for a selected approved fluid.