Submitted to: Pan Pacific Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/8/2014
Publication Date: 3/31/2015
Citation: Yee, W.L., Lawrence, T.W., Hood, G.R., Feder, J.L. 2015. New records of Rhagoletis species (Diptera: Tephritidae) and their host plants in western Montana, U.S.A.. Pan Pacific Entomology. 91:39-57. Interpretive Summary: Fruit flies of the genus Rhagoletis comprise a major group of quarantine pests of economically important fruits in the western U.S. Documenting the geographic and host ranges of these flies can help better manage the pests and also provide new information on their biology. Personnel at the USDA-ARS Yakima Agricultural Research Laboratory in Wapato, WA, Flathead Lake Cherry Pest Control Board in Bigfork, MT, and the University of Notre Dame, IN determined the presence of seven species of Rhagoletis flies in Montana, of which four had never been reported in the state. New records of host plant use by several fly species were also determined. Among the new fly records was apple maggot fly, a major quarantine pest of apples. Results expand the known geographic and host ranges of Rhagoletis flies and imply that movement of apple maggot host fruit from Montana to apple-growing regions of the western U.S. should be restricted.
Technical Abstract: Little information exists concerning the distribution of Rhagoletis fruit flies (Diptera: Tephritidae) in the state of Montana in the western U.S.A. In this study, the presence of and host plant use by Rhagoletis species are documented in northwestern Montana. The western cherry fruit fly, Rhagoletis indifferens Curran, 1932, was abundant and infested sweet (Prunus avium [L.] L.), mahaleb (P. mahaleb L.), tart (P. cerasus L.), and bitter cherry (P. emarginata [Douglas ex Hook.] D. Dietr.) (Rosaceae) in the state. In contrast, the black cherry fruit fly, R. fausta Osten Sacken, 1877, was very rare and detected only in bitter cherry. Rhagoletis berberis Curran, 1932, R. basiola (Osten Sacken), 1873, R. tabellaria (Fitch), 1855, and the apple maggot, R. pomonella (Walsh), 1867, were all recorded for the first time in Montana. Flies in Montana were mainly reared from previously reported species of host plants, but new host records were also documented: (1) one R. indifferens fly from black hawthorn, Crataegus douglasii Lindl. (Rosaceae), a new Montana record; (2) R. berberis from sweet cherry; (3) R. basiola from baldhip rose, Rosa gymnocarpa Nutt. (Rosaceae); and (4) R. tabellaria from Hooker’s fairy bells, Prosartes hookeri Torr. (Liliaceae). Rhagoletis pomonella, which was likely introduced into the western U.S. within the last 60 years, was reared from C. douglasii, but not from domesticated apple (Malus domestica Borkh.), although in the latter case relatively few fruit were sampled. The findings extend the known geographic ranges of four Rhagoletis species and indicate that some flies in northwestern Montana have the ability to survive and develop in alternative and novel hosts, consistent with findings for populations in other areas of the western U.S.