This pest report supersedes the pest report posted on July 14, 2004. Additions to the report are in red text.
Numerous Frankliniella intonsa (Trybom) Eastern flower thrips have been intercepted at the Canadian/Washington border from shipments of cut flowers. From August through October 2003, surveys in Washington State discovered F. intonsa on several weed species in King County on red clover in Skagit County on chrysanthemum in Snohomish County, and on sticky traps on raspberry farms in Whatcom County. Shortly after the detections in Washington State, fall surveys in nurseries in Oregon were positive for the thrips. Cut flowers, which are the most common pathway of dispersal, were removed from the ‘line release’ system and were subject to inspection as of October 8, 2003.
F. intonsa, a pest of cut flowers and vegetable crops, inhabits most temperate regions of the world including Europe, Asia, Turkey, British Columbia, and Canada. The first report of F. intonsa in the United States was in Washington State in 1972; however, surveys in the 1990s from the previously documented site were negative.
F. intonsa is an efficient vector of tomato spotted wilt virus (TSWV), and can transmit tomato chlorotic spot virus (TCSV), groundnut ring spot virus (GRSV), and impatiens necrotic spot virus (INSV) at low efficiencies. TSWV and INSV are present within the United States. Although TCSV and GRSV are currently exotic but potential threats to crops, Frankliniella occidentalis, Western flower thrips, an established U.S. species, is a more efficient vector of both viruses.
All states are asked to check their insect collections for specimens of F. intonsa. Extra care should be given to examine specimens of the closely related Western flower thrips F. occidentalis, which can be easily mistaken for F. intonsa.
States are asked to report positive and negative results from the survey of collections to the National Agricultural Pest Information System Database so that PPQ can determine the extent of the U.S. distribution. This information is needed in order to determine whether or not to continue regulatory actions for this pest. Until such a determination is made, F. intonsa will continue to be treated as a regulated pest. Please communicate findings no later than September 1, 2004, to
Coanne O’Hern (National Survey Coordinator) at (301) 734-4387, or e-mail Coanne.E.O’Hern@aphis.usda.gov.