Polyethylene support in form of net or fabric, comprising, grafted on the surface of said support, a hydrogel comprising polyvinylpyrrolidone and absorbed to the hydrogel a pyrethroid. Method for preparing said support comprising the steps of: immersing the support in a toluene solution (Soil) containing: ethylene glycol dimethylacrylate (EGDMA) and cumene hydroperoxide (CHP); immersing the support in an aqueous solution (Sol2) containing: FeCl2 * 4H20, ascorbic acid and polyvinylpyrrolidone (PVP); washing and drying the support.
