Abstract: The present invention discloses a device for controlling the application of insecticides for indoor residual spraying using a sprayer comprising a lance with a spray nozzle, a distance sensor configured to measure the distance between the spray nozzle and the surface being sprayed, an indicator of the distance measured by said sensor, and an indicator of the spraying rate and means of attachment to the sprayer lance and a pipe which allows the insecticide to pass through, and in that the indicator of the distance measured comprises a luminous device which changes colour according to the distance measured by said sensor; a method of applying insecticides for indoor residual spraying by the use thereof, the use thereof to control the application of insecticides and a sprayer which comprises a control device according to the present invention.