Submitted to: Annals of the Entomological Society of America
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/21/2005
Publication Date: 9/15/2005
Citation: Yee, W.L., Goughnour, R. 2005. New hosts of western cherry fruit fly, Rhagoletis indifferens (Diptera: Tephritidae), and their relationship to life history characteristics of this fly. Annals of the Entomological Society of America. 98(5):703-710. Interpretive Summary: Western cherry fruit fly is a serious pest of cherry 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 determining the role of new hosts on the biology of the flies. Three new hosts were discovered in 2001-2003: cascara, black hawthorn, and cherry laurel. Flies infested fruit of these hosts in the tree study seasons, and adults were consistently caught on traps placed in these hosts. Flies from all hosts survived equally long periods in the laboratory and some laid substantial numbers of eggs. The results of this study are important in that they indicate the cherry fruit fly can utilize non-cherry hosts. Use of the new hosts may result in the development of new fly races and in some cases may also result in reservoir populations of flies that migrate to cherry trees, making fly management more difficult.
Technical Abstract: Two native trees and one introduced tree in the coast forest ecosystem in southwestern Washington State were identified as new host records for the western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), in 2002 and 2003. Key biological characteristics of flies on or from the new hosts were also examined. Larvae infested native cascara, Rhamnus purshiana De Candolle, native black hawthorn, Crataegus douglasii Lindl., and introduced cherry laurel, Prunus laurocerasus L., along with the known hosts, native bitter cherry, Prunus emarginata (Dougl.) D. Dietr., and introduced sweet and sour cherries, Prunus avium (L.) and Prunus cerasus L. Infestations of the new hosts and bitter cherry were lower than in sweet and sour cherries. Rearing of larvae to adults confirmed cascara, black hawthorn, and cherry laurel are suitable developmental hosts. In addition, two flies reared from cascara had wing patterns never reported before, with one keying out to R. indifferens. Adult R. indifferens were consistently caught on unbaited sticky yellow panel traps in cascara, black hawthorn, and cherry laurel. Seasonal patterns of adult abundance were similar in these hosts and in bitter cherry, with most flies caught beginning in mid July after fruit were no longer green. Fruit of all hosts ripened at similar times. On cascara and black hawthorn, R. indifferens was seen feeding on damaged fruit, and on black hawthorn, flies mated with the non-native apple maggot, R. pomonella (Walsh). The longevity of flies reared from cascara, cherry laurel, bitter cherry, and sweet and sour cherry were similar, averaging 37.7 to 85.6 days. However, body masses or fecundity of flies from cascara, cherry laurel, and bitter cherry were generally lower than those from sweet cherry. In contrast to the coast forest ecosystem, neither cascara nor cherry laurel was found at sites studied in ponderosa pine and sagebrush-bunchgrass ecosystems in central Washington in 2003 and 2004. Adults were not caught on unbaited traps in black hawthorns in these two ecosystems, and no larvae were reared from haws from either ecosystem.