Scirtothrips dorsalis is a serious exotic pest that has recently become established in the con tinental United States. It is of major concern to regulatory agencies because it has a wide host range and high reproductive potential. A weather-based mapping tool, NAPPFAST, was used to predict potential establishment of S. dorsalis in North America. The analysis was based on a degree-day model and cold temperature survival of S. dorsalis. The results demonstrated that S. dorsalis could potentially produce up to 18 generations and was likely to survive in the southern and western coastal plains of the United States. It is concluded that S. dorsalis is likely to be a serious economic pest in the southern United States. Addi tional maps and information are available at the web site (http://www. nappfast. org).