Detection of Scolytus schevyrewi Semenov in Colorado and Utah
On May 13, 2003, the Agricultural Research Service, Systematic Entomology Lab confirmed that specimens of Scolytus schevyrewi Semenov (S. schevyrewi), an exotic scolytid previously unknown in the United States, had been collected in Colorado and Utah. Between April 1 and May 9, 2003, S. schevyrewi was collected near two Colorado solid wood packing material recyclers (3 specimens from one site and 67 from another) at the Denver Zoo (two specimens) and from sites in Ogden, Logan, Clearfield, and Smithfield, Utah (13 specimens). Since early May, the APHIS/Forest Service Rapid Detection and Response Pilot Project team in coordination with State officials continue to discover S. schevyrewi in Colorado and Utah. To date, this species has not been reported from other States. Hosts of S. schevyrewi include Elaeagnus spp. (Russian olive), Salix spp. (willow), Ulmus spp. (elm), Caragana spp. (peashrub), and Prunus spp. Research from Asia indicates that S. schevyrewi does not colonize and breed successfully in healthy elms; the beetle attacks trees that have been weakened and predisposed to attack by drought, severe defoliation or pathogen invasion. Scolytus schevyrewi may produce several generations per year. The potential for S. schevyrewi to vector exotic pathogens is currently unknown and is a possible concern. The known distribution of S. schevyrewi outside the United States is Russia and Mongolia and central, northwestern, northern, northeastern and eastern China and Korea. The New Pest Advisory Group (NPAG) held a teleconference May 21, 2003, regarding S. schevyrewi and to collect information from subject-matter experts. Topics discussed included potential economic and environmental impacts on urban, rural, and forest trees; the need and logistics for delimiting/detection survey including the identification of high- risk areas (major rail yards in the Plains and Western States near host material); pathway and regulatory issues; and the need to investigate pathogenic fungal relationships with S. schevyrewi. Additional actions may be required when the range of distribution is established and exotic pathogen relationships are determined.