Stored grain insect pests cause high deterioration to grains and seeds in storage, such as weight loss, less germination and reduced nutrition values of grains. In the present study,theefficacyof threenano-particlesnano-malathion, organic nano-silica and inorganic nano-silicawereevaluated by mixing with grains under laboratory conditions against the adults ofTriboliumcastaneum. (Herbst) (Coleoptera: Tenebrionidae).The results showed that nano-malathion had the highest adverse effect on all parameters after 14 days of treatment. The median lethalconcentrations (LC_50s) of organic nano-silica and inorganic nano-silica on adultsof T. castaneum were2.76 and 0.90% after10 days of treatment, respectively. The lethal concentration (LC₅₀) of nano-malathion was 34×10^-5%while the (LC₅₀) of conventional malathion was 0.10% after 3 days of treatment.Inorganic nano silica showed significant inhibitor on the number of T. castaneum adult progeny at the lower concentration.