Abstract: The western flower thirps, Frankliniella occidentalis （Pergande）, is a worldwide pest, causing serious damage to a wide range of host plants. It was first reported in China in 2003, with a trend of further spreading. Most of thrips species are small in size and similar in morphology, which makes them hard to be distinguished quickly. In the present research, a pair of SCAR （sequence characterized amplified regions） primers （FOMF/FOMR） which are specific to western flower thrips was developed by using other nine familiar thrips species as the control. The fragment amplified by the primers FOMF/FOMR was 320 bp in length. Specificity tests performed with this pair of primers showed that all F. occidentalis specimens were detected positively and no cross reactions with other 41 thrips species, including F. intonsa （Trybom）, F. tenuicornis （Uzel） and Thrips tabaci L., were detected. The method was tested on single male and female adult, single pre-pupa and pupa, single 1st- and 2nd-instar larva, and even single egg, and proved to be applicable for these stages of F. occidentalis. Moreover, the 320 bp genomic DNA fragment was clearly identified in the host plant tissues collected in F. occidentalis infested areas. When the dilution was 1/160 of a whole female adult of F. occidentalis, the 320 bp DNA fragment could be identified for all replicates. The technique should be useful in quarantine at ports and in pest detection and monitoring during transportation of flowers, vegetables and seedlings.

Key words: Frankliniella occidentalis, RAPD-PCR, SCAR marker, rapid detection, specific amplification, detectable threshold limit value