【Background】Opisina arenosella Walker, a new invasive insect, caused serious economic losses to palm plants.【Method】By the method of leaf immersion, the toxicities of 5 insecticides to 5th~6th instars larvae of O.arenosella was tested under laboratory conditions.【Result】After 72 h of exposure, the most toxic compound was emamectin benzoate, followed, in decreasing order, by chlorantraniliprole,chlorpyrifos, lambda-cyhalothrin, and nicotine. The lethal concentration (LC50) values were 5.2604 mg·L-1, 9.7126 mg·L-1, 24.8202 mg·L-1, 104.0584 mg·L-1, 643.1496 mg·L-1 respectively. To reach an identical level of toxicity, the cheapest compund was chlorpyrifos, followed by, in increasing order, emamectin benzoate, lambda-cyhalothrin, chlorantraniliprole and nicotine. 【Conclusion and significance】When there is a need for emergency control of O.arenosella on the basis of toxicity and cost, we recommended to use chlorpyrifos and emamectin benzoate for controlling O.arenosella.