We surveyed 13 Finnish and 13 Swedish poinsettia greenhouses in 2006 for Bemisia tabaci biotype Q (currently B. tabaci Mediterranean) and determined the biotype status of B. tabaci populations with PCR followed by an RFLP assay. We collected approximately 100 adult whiteflies from yellow sticky traps or from plants and stored them in 80% ethanol until DNA extraction. Total nucleic acids of two to five whiteflies per sample were extracted using FTA cards or a modified Chelex method. We showed that biotype Q was present in 10 out of 13 whitefly samples from Finnish poinsettia greenhouses and in 12 out of the 13 Swedish poinsettia greenhouses sampled. We also determined the whitefly biotypes from yellow sticky traps. The common occurrence of insecticide-resistance-prone biotype Q whiteflies on poinsettia imported into Finland and Sweden, both protected zones for B. tabaci, emphasizes the importance of preserving the quarantine status of the pest to prevent permanent establishment. Nonetheless, the increasing occurrence of a resistance-prone biotype on imported plant material will complicate preservation of the protected zone status if solely insecticides are used to control the pest.