The present invention deals with a microbiocidal aqueous formulation comprising: (i) an effective amount of at least one essential oil component, or derivatives thereof, said derivatives thereof obtained by exposure to light or by oxidation, or mixtures thereof; and (ii) at least one additional stabilizer selected from the group consisting of ethanol in an amount of from 10% to about 50%, an emulsifier, an antioxidant, or an encapsulating agent. The invention is further directed to a method for inhibiting microbial development using said microbiocidal aqueous formulation.