Abstract: To characterize the developmental trend of resistance to insecticides of oriental leafworm moth （OLM）， Spodoptera litura， in Zhejiang province， the sensitivities to 11 insecticides of OLMs collected from Sanmen and Xiaoshan were studied and compared. Significant differences were shown between the data of OLMs from the two cities， i.e. the acquired sensitivities to 11 insecticides of OLMs from Sanmen were higher than those of OLMs from Xiaoshan. Refering to the survival rate of OLMs after treating at discriminating doses， together with the ratio of insecticidal LC99 to field recommended concentration， it could be deduced that OLMs in Sanmen was still sensitive to chlorantraniliprole， chlorfenapyr; sensitivities to indoxacarb， emamectin benzoate， chlorfluazuron， diafenthiuron， spinosad have declined; and resistances to tebufenozide， spinetoram and beta\|cypermethrin have developed. While the OLMs in Xiaoshan were sensitive to chlorantraniliprole， chlorfenapyr and spinosad; sensitivity to emamectin benzoate， diafenthiuron， chlorfluazuron， spinetoram， indoxacarb， abamection had declined， and resistances to beta\|cypermethrin have developed. Therefore， resistance levels of OLMs to most of the insecticides monitored were increasing in Zhejiang province， and beta\|cypermethrin， abamection， tebufenozide that OLMs had developed resistance should be stopped using for one or two years， and the rest still can be applied to control OLMs by the methods of limiting the frequency of spraying， rotation or mixture of different kinds insecticides in order to delay the development of resistance.

Key words: Spodoptera litura, insecticide, sensitivity