LARVEXproducts do not act as chemicals, they are derivatives of natural vegetable oils known as "water insoluble surfactants" and are completely non toxic and biodegradable. They have the property of rapidly spreading on the surface of the water to give a monomolecular film. Since the Larvex is biodegradable, considerably more than the minimum is required per hectare.

As LARVEXmonolayers do not act by a chemical or biochemical toxic action, but by a physical ‘wetting’ action, this permits the water to enter the hydrophobic breathing passages, causing oxygen deprivation, asphyxia and drowning. This action is rapid in the case of pupae that can only obtain the necessary oxygen whilst at the surface. Larvae however can respire using dissolved oxygen and are less dependant on obtaining aerial oxygen at the surface.

Another important factor is that since the mechanism of LARVEX is physical and not chemical the prospect of the evolution of resistant mutants is very low indeed.

Anopholenes most affected by monolayers, then Aedes followed by Culicenes.