Numerous Frankliniella intonsa (Trybom) 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 surveys in Washington State, fall surveys in nurseries in Oregon were positive for the thrips (later verified by SEL).
Frankliniella intonsa, a pest of cut flowers and vegetable crops, inhabits most temperate regions of the world including Europe, Asia, Turkey, and British Columbia, 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.
Frankliniella 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, Frankiliniella occidentalis, an established species, is a more efficient vector of both viruses.
Cut flowers, which are the most common pathway of dispersal, were removed from the ‘line release’ system as of October 8, 2003. States are urged to check their collections for specimens of F. intonsa. Extra care should be given to check the closely related Western flower thrips F. occidentalis, which can be easily mistaken for F. intonsa.