Alternative material for controlling of the fourth instar larvae of cotton leafworm, Spodoptera littoralis (Boisduval) was used alone and in combination with some insecticides. Silica as a new material in pest control was used alone and combined with chlorpyrifos, imidacloprid and chlorantraniliprole. The results showed that chlorantraniliprole was the most toxic against S. littoralis larvae than other. The LC50 of chlorantraniliprole was 0.17 ml/l compared with 1.26 g/l, 1.0 ml/l and 0.22 g/l for silica, chlorpyrifos and imidacloprid, respectively. When silica was combined with one - fifth of the field rate of the tested pesticides, the percent of mortalities for chlorpyrifos silica mixture against the 4th instar larvae of S. littoralis was increased to 96.7, 76.7 and 33.3 % with the first, second and third concentrations, respectively. The percents of mortalities for imidacloprid (one - fifth of the field rate) silica mixture and chlorantraniliprole (one - fifth of the field rate) silica mixture were decreased slightly, compared to imidacloprid and chlorantraniliprole alone. It was 78.3 and 85.5 %, 48.3 and 56.7%; and 21.7 and 28.3% for the first, second and third concentrations, respectively, compared to 76.7 and 93.3%, 51.7 and 68.3%; and 33.3 and 36, respectively. These results suggested that silica as a low cost material was moderately toxic against the 4th instar larvae of S. littoralis (43.3%) when treated alone and it can be used in combination with the tested pesticides to activate the pesticides toxicity, reduce the pest control costs and reduce the pesticides hazards.