The present invention relates to a bait box made of plastic and comprising at least 1 lateral access adapted to the pest to be controlled and at least 1 fill port arranged at the top and adapted to the introduction of bait gel; a system for the use of gels in pest control, consisting of a bait box and an applicator; the use of the bait box and the system; a method of controlling pests. A controller measures the time of flight of a light beam that is reflected from the retroreflective target. The photodetector circuit has a function of generating an optical data signal.