Abstract: The second internal transcribed spacers (ITS2) of six Trichogramma species, i.e. T. dendrolimi Matsumura, T. ostriniae Pang et Chen, T. chilonis Ishii, T. evanescens Westwood, T. brassicae Bezdenko and T. embryophagum (Hartig) were cloned and sequenced, and the homological sequences available in GenBank retrieved for DNA alignment and clustering. The feasibility of the application of ITS2 sequences to the phylogenetic reconstruction and molecular identification of different Trichogramma species was then evaluated. Meanwhile, six geographical populations of T. dendrolimi, i.e., populations collected from Yabuli in Heilongjiang (YBL), Changchun in Jilin (JL), Renhe in Jilin (RH), Chang'an in Shaanxi (CHA), Xuzhou in Jiangsu(XZ) and Guangzhou in Guangdong(GZ), were used to determine ITS2 divergence between subspecies populations. Alignment of sequenced ITS2s showed that they were highly conserved within intraspecific taxa but that significant genetic distances existed between interspecific taxa. Comparison and analysis of an outgroup led to the clear conclusion that ITS2 is suitable only for species-level identification.

Key words: Trichogramma; Uscana, rDNAITS2, molecular identification, molecular systematics