The invention concerns a device for combating the proliferation of aquatic larvae in containers likely to hold stagnant water, said containers (1) comprising a wall (2) defining a cavity (3) and an open hole (4), and comprising an element (10) of which the shape is designed to completely or partially conform to that of the wall (2) of said cavity and to seal said hole, said element being produced from a porous material permeable to air and to water, comprising a rubber granulate and a synthetic binder. The device made from porous material occupies the opening of the tank which can therefore no longer be freely accessed by mosquitoes. The present invention also concerns a method implementing such a device.
