关键词: 菜蛾啮小蜂, 小菜蛾, 寄生习性, 温度, 种群增长

Abstract: Oomyzus sokolowskii (Kurdjumov), a major parasitoid of the diamondback moth, Plutella xylostella L., is a larvalpupal parasitoid that prefers ovipositing into host larvae of all instars but depositing its eggs in host prepupae too. The parasitoid can also deposit eggs into grown larvae of Cotesia plutellae (Kurdjumov) that have been parasitizing the larvae of diamondback moth. Thus, O. sokolowskii is a facultative hyperparasitoid of the diamondback moth In Hangzhou, the parasitoid is active in the field from April to October, and enters into a quiescent state as matured larvae or prepupae inside the hosts in midto late October to overwinter until next April. Laboratory experiments showed that the favourable temperature for development, survival, and reproduction of the parasitoid ranged from 20 to 30℃, and temperatures below 20℃ or above 30℃ were unfavourable for its survival. However, the wasps that developed and emerged at favourable temperatures could effectively parasitize the host at 32～35℃ in a short period of time. At 20℃, 25℃ and 30℃, a female wasp on average parasitized 3.1, 13.2 and 6.8 larvae of the diamondback moth, and produced 20.5, 92.1 and 50.4 offsprings, respectively. The intrinsic rates of increase (r_m) of the parasitoid at 20℃, 25℃ and 30℃ were estimated to be 0.082, 0.240 and 0.263 female/female/day, respectively.

Key words: Oomyzus sokolowskii, Plutella xylostella, parasitization, temperature, population growth