Stop larvae has only an action of physical-mechanical type. The thin silicone film,which is formed on the water surface following the application, prevents the proper development of the immature stages of mosquitoes (larvae and pupae). It does not allow the larvae and pupae to the correct intake of atmospheric oxygen necessary for their development to adult stage, bringing the consequent suffocation. In fact, it prevents larvae and pupae from sticking to the surface of the water to draw from the atmospheric oxygen needed to survive. The low surface tension, also has an impacton spawning in qunto adult females do not lay their eggs on the water treated.