The tests of four essential oils against 4 species of storedproduct insects, Sitophilus zeamais, Tribolium casta-neum, Oryzuephilus surinamensis and Rhizopertha dominica,insimulated storehouse were carried out in Guangdong Province. The results showed that cassia oil at a dosage of 0. 2% by seed dressing kept the stored wheat free from damage by insects for as long as 8 months. Using a dosage of 0. 45 mg/cm2 to treat gunnysack, the essential oils from Illici-um verum and Clausena dunniana protected the wheat from being damaged by stored-product insects for 4 months, whereas cassia oil for as long as 8 months. The results of experiments in storehouse indicated that the combination of 15 ppm cassia oil caused 100% mortality of stored-product insects and 30 ppm malathion or 30 ppm cassia oil caused tested insects 89. 5% and 98. 5% mortalities, respectively.