A nozzle spray assembly for insecticide that can be readily connected to an outlet pipe of an air blower to conveniently spray an area free of insects. A friction fit between shoulders on the plug and a rib and ledge inside of the rail is attained by the relative spacing of the shoulders to the spacing of the rib and ledge. The board can be made from reused or biodegradable materials thus creating a device that is both cost-effective and less harmful to the environment. The safety construction comprises at least two mutually firmly connected elements which upon exceeding of a defined threshold load are separated and movable with respect to one another.