Abstract: The invasive species Echinothrips americanus Morgan, 1913 (Thysanoptera: Thripidae) was recently found in Beijing, China. Both morphological and molecular methods were used to identify this species. External morphology of different stages was observed and recorded under stereo microscope. A 430 bp segment of mitochondrial COⅠ gene was amplified and sequenced from this species for molecular identification. Based on all coding positions and 1st and 2nd coding positions of mitochondrial COⅠ genes, the phylogenetic tree of the newly found species together with other 38 thripid species was constructed. The tree based on matrix composed of 1st and 2nd coding positions using NJ method could resolve the identification of thripid species better than that composed of all codon positions using other methods. This method provides an easy way to detect the dispersal of this species in other areas. Finally, biological characteristics of this thrips and the control measures were discussed.

Key words: Echinothrips americanus, invasive pest, morphology, molecular identification, DNA barcoding, biology