Submitted to: Pan-Pacific Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2005
Publication Date: 6/1/2006
Citation: Yee, W.L., Goughnour, R. 2006. New host records for the apple maggot, Rhagoletis pomonella (Diptera Tephritidae) in Washington State. Pan-Pacific Entomologist. 82(1): 54-60. Interpretive Summary: The apple maggot fly is a serious quarantine pest of apples in the Pacific Northwest, and knowledge about the biology of flies is needed to manage the fly. Personnel at the Yakima Agricultural Research Laboratory in Wapato, WA, are identifying new hosts of the flies. Two new hosts were discovered in 2001-2004: Asian pear and bitter cherry. In addition, three new host records were established: common pear, plum, and cotoneaster. The results of this study are important in that they indicate apple maggot flies in Washington have a greater host range than previously assumed. This means that these plants may need to be included in a fly detection program to prevent fly establishment in major apple-growing areas.
Technical Abstract: A study was conducted to establish new host records for the apple maggot, Rhagoletis pomonella (Walsh) (AM), in southwestern Washington and to test the hypothesis that these hosts are used consistently (yearly) by this fly. Based on flies reared from fruit collected in 2001-2004, Asian pear, Pyrus serotina L., bitter cherry, Prunus emarginata (Doug. Ex. Hook) D. Dietr., common pear, Pyrus communis L., garden plum, Prunus domestica L., and spreading cotoneaster, Cotoneaster divaricatus Rehd. and Wils., were confirmed AM hosts, in addition to apple, hawthorns, and crabapple (all hosts belong to the Rosaceae). Asian pear has never been recorded as a host for AM. Asian pear was infested for four consecutive years, supporting the hypothesis that it is used consistently and that AM may even be capable of establishing in this host. Bitter cherry, a common native tree throughout most of western and northeastern Washington, is also a new host record for AM. Common pear, plum, and cotoneaster are new published host records for AM in Washington State. The species C. divaricatus has not been recorded as a host in any locality. The results support the hypothesis that common pear and plum are used consistently by AM. Cotoneaster divaricatus was rare and probably used infrequently, perhaps only when it is ripe during late season near infested apples or hawthorns. If AM populations increase in or near the major apple-growing areas of central Washington, Asian pear, pear, and plum may occasionally be attacked and may need to be monitored in a fly detection and suppression program.