Submitted to: Pan Pacific Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/14/2008
Publication Date: 12/12/2008
Citation: Yee, W.L. 2008. Host plant use by apple maggot, western cherry fruit fly, and other rhagoletis species (diptera: tephritidae): in central washington state. Pan Pacific Entomology 84(3):163-178. Interpretive Summary: Apple maggot and cherry fruit flies are important quarantine pests of apples and cherries in the Pacific Northwest. Knowledge about the host plant use by these flies in western Washington, where the flies occur at very high densities, is important because it can be used to determine the potential host range of the flies in central Washington, where the commercial fruit growing industry is concentrated. Personnel at the USDA-ARS Yakima Agricultural Research Laboratory in Wapato, WA, are determining the host plant use of these flies by collecting fruit and rearing flies from them. We found that apple maggot flies breed in a wider range of plants in western than central Washington, including non-commercial apple, hawthorn, crab apple, pears, plum, ashes, and other plants. Cherry fruit flies also breed in more plants in western than central Washington. Results suggest both flies can breed in plants other than apples and cherries in central Washington and affect monitoring and control efforts. However, the relatively low densities of at least apple maggot in central Washington may explain why other host plants are not used there at present.
Technical Abstract: Host plant use by apple maggot fly, Rhagoletis pomonella (Walsh), western cherry fruit fly, Rhagoletis indifferens Curran, and other Rhagoletis species (Diptera: Tephritidae) in western Washington state and northwestern Oregon were determined by rearing larvae in fruit to adults in 2004 to 2006. Rhagoletis pomonella infested apple, Malus domestica (Borkh.) Borkh., crab apple, Malus spp., black hawthorn, Crataegus suksdorfii (Sarg.) Kruscke, and English hawthorn, Crataegus monogyna Jacq. Also infested were apricot, Prunus armeniaca L., and cherry plum, Prunus cerasifera Ehrh., which are two new Washington host records for R. pomonella, and smooth hawthorn, Crataegus laevigata (Poiret) DC., Japanese plum, Prunus salicina Lindl., European mountain ash, Sorbus aucuparia L., western mountain ash, Sorbus scopulina Greene, parney cotoneaster, Cotoneaster lacteus W. W. Smith, and European cotoneaster, Cotoneaster integerrimus Medic., which are six new host records for R. pomonella. Rhagoletis indifferens infested bird cherry, Prunus padus L., and cherry plum, P. cerasifera, which are two new host records. Three, one, and one new host records were also determined for Rhagoletis tabellaria (Fitch), Rhagoletis zephyria Snow, and Rhagoletis completa Cresson, respectively. In the coast forest ecosystem of western Washington, the host breadth of both R. pomonella and R. indifferens are relatively broad, perhaps in part because of large fly populations. The discovery of 13 new hosts in western Washington suggests this region can yield a wealth of information on the adaptability of various Rhagoletis to diverse plants and host race formation in this genus.