Abstract: 【Aim】Chelonus formosanus is an important parasitic natural enemy of a variety of lepidopteran pests. This study aims to identify and screen the suitable cold storage conditions of C. formosanus to extend its shelf life.【Methods】After the 7-day-old pupae of C. formosanus were stored at 5, 9 and 13 ℃ for 5, 10, 15, 20 and 25 d, respectively, the adult emergence rates, adult longevity, numbers of eggs laid by female adults in 24 h and adult parasitism rates, and adult emergence rates, proportions of females and adult longevity of progeny were observed and compared.【Results】When the 7day-old pupae of C. formosanus were stored at different low temperatures, the adult emergence rates and adult longevity decreased with the extension of storage time. At the same storage time except 5 d, the adult emergence rate showed an upward trend with the increase of temperature, and the adult emergence rate in the cold storage group at 13 ℃ was significantly higher than those in the cold storage groups at 5 and 9 ℃. Under the storage conditions of 9 and 13 ℃, with the extension of storage time, the number of eggs laid by female adults in 24 h showed a downward trend. After the 7-day-old pupae were stored at 9 ℃ for 10 and 15 d, the adult parasitism rates were significantly lower than that of the control group (stored at 24 ℃), and the adult parasitism rates between the other cold storage treatments and the control group showed no significant difference. When the 7-day-old pupae were stored at 5 ℃ for 5 d, the proportion of females of progeny was the lowest (only 35.27%). When the 7-day-old pupae of C. formosanus were stored at 13 ℃, the proportion of females of progeny showed no significant difference from that of the control. When the 7-day-old pupae of C. formosanus were stored at different low temperatures, the adult emergence rate and adult longevity of progeny did not differ significantly from those of the control group.【Conclusion】It was recommended that the 7-day-old pupae of C. formosanus should be stored at 13 ℃ for no more than 15 d.

Key words:  Chelonus formosanus, cold storage, adult emergence rate, adult longevity, parasitism rate