Abstract: This paper systematically studied,with the sealed jar fumigation method under different conditions,the effects of ethylformate (EtF) on eggs,early larvae,late larvae,pupae and adults of C.turcicus.Experiments signify the corresponding corrected mortalities of adults were 88.633% and 99.453% with 0.040 and 0.045 EtF volume ratio after 12　h fumigation under 28　℃.And the adult corrected mortalities were 84.367%,88.087%,92.376%,74.266%,63.252%,60.953% and 58.775% respectively with 35　μL/L dosage after 24 h fumigation under 15,18,21,24,27,30 ℃  and 33 ℃.These results indicated that the EtF killed the adult weevils in a very short time period,and the fumigation efficacy was better at relatively lower temperature than that at relatively higher temperature.Under the conditions of 20,25,30 ℃ after 24 h fumigation,the volume ratio LC50　s were 0.014 311，0.017 335　and 0.021 073 respectively,whereas after 48　h fumigation,the corresponding volume ratio LC50　s were 0.012 828，0.015 446 and 0.020 068.Fumigating the immature stages of C.turcicus 24　h with 30　g/m３ dosage EtF,the mortalities of eggs,early larvae,late larvae and pupae of were 93.372%,99.782%,96.638% and 91.645% respectively，which proved that the fumigation activity of EtF was the best against early larvae,and the pupae and eggs possessed a relatively high endurance to EtF.

Key words: ethylformate, cryptolestes turcicus(growville), fumigant activity