Insecticide-containing polymeric material comprises deltamethrin and a UV stabilizer, where the material has an R-alpha -isomer content of the deltamethrin of less than 10 wt.%. Independent claims are included for: (1) producing the insecticide-containing polymeric material, comprising melting the polymer, deltamethrin, UV stabilizer and optionally other insecticides or additives together or separately at 120-250[deg] C and then cooling and solidifying the polymer mixture and its division into granules; and (2) producing filaments, fibers, threads and yarns, comprising melting the insecticide-containing polymeric material, forming into strands and cooling, conducting and stretching the resulting gossamer on a stretcher system, and finally fixing and/or relaxing the filaments, fibers, threads and yarns.