Submitted to: Pan Pacific Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 14, 2008
Publication Date: December 12, 2008
Citation: Yee, W.L., Goughnour, R.B. 2008. Host Plant Use by and New Host Records of Apple Maggot, Western Cherry Fruit Fly, and Other Rhagoletis Species (Diptera: Tephritidae). I. Central Washington State. Pan Pacific Entomology 84(3):179-193. 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 central Washington, a major fruit production area, is critical in fly management and control efforts. 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 non-commercial apple and wild hawthorn near commercial growing areas, but that the density of flies is very low. Most are found in hawthorn. Non-commercial apple and hawthorn were the only two hosts of apple maggot flies found. Cherry fruit flies infested only various cherries and no other hosts. Results suggest that even though it is present, apple maggot fly likely can be managed to meet the strict quarantine requirements of apple export because of its low density. Cherry fruit fly management can be confined to cherry trees.
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 five cities or towns and several habitats of difference commercial importance within south central Washington state was determined in 2004 to 2006. Rhagoletis pomonella larvae infested 0 to 1.6% of non-commercial apple trees, Malus domestica (Borkh.) Borkh., and 0 to 22.5% of wild black hawthorn, Crataegus douglasii Lindl., the first data showing R. pomonella has established within this part of the state. Rhagoletis indifferens infested 81.8 to 100% of non-commercial sweet and sour cherry trees (Prunus avium (L.) L. and Prunus cerasus L.) (0% in one area) and 21.7 to 94.7% of wild bitter cherry trees, Prunus emarginata (Dougl. ex Hook.) D. Dietr. Rhagoletis zephyria Snow, Rhagoletis basiola (Osten Sacken), Rhagoletis tabellaria (Fitch), Rhagoletis berberis Curran, and Rhagoletis completa Cresson infested their hosts at frequencies of 0 or 15.4 to 100% of plants. In south central Washington, the host breadth of R. pomonella is narrow perhaps because of the hot and dry conditions, low fly densities, and low host plant abundance outside of orchards. Here, R. pomonella likely can be managed to meet the strict quarantine requirements of apple export. Rhagoletis indifferens management can be confined to sweet and sour cherry trees. Responses of various Rhagoletis species to plant cues and survival of flies in dry climates need to be determined to understand patterns of host use and population densities in Washington.