Submitted to: Environmental Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/27/2007
Publication Date: 4/5/2008
Citation: Yee, W.L. 2008. Feeding substrates and behaviors of western cherry fruit fly (Diptera: Tephritidae). Environmental Entomology. 37(1):172-180. Interpretive Summary: Western cherry fruit fly is a serious pest of commercial cherry in the Pacific Northwest, but insecticides used in the past will no longer be available for use by growers in the near future. Knowledge about the feeding ecology of the fly may be helpful in developing strategies, lures, or attractants in environmentally-friendly bait sprays for fly control. Personnel at the Yakima Agricultural Research Laboratory in Wapato, WA are determining the feeding ecology and foods used by flies in nature. Extensive observations indicated flies fed mostly on cherry leaf surfaces and not on cherry fruit. On leaves, flies fed mostly on undetermined substances rather than cherry juice, bird droppings, or extrafloral nectarines. More flies fed on the top than bottom surfaces of leaves. Flies also fed on leaves of non-cherry trees. The results of this study are important in that they show that baits mixed with insecticides sprayed on the tops of cherry leaves will be ingested by flies engaged in their normal feeding behaviors, which may lead to effective control.
Technical Abstract: A study was conducted to determine the abundance of potential foods and the feeding substrates of the western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), in 2005 and 2006 in central Washington. Aphid colonies with honeydew were not seen on randomly selected branches of sweet cherry trees, Prunus avium (L.) L., but leaves with cherry juice, fruit that were injured, and leaves with bird feces were commonly seen later in the season. Grazing on leaves (assumed to be a feeding behavior) occurred much more frequently than feeding on extrafloral nectaries (EFNs) on leaf petioles, cherry juice on leaves, and bird feces on leaves. Feeding rarely occurred on fruit. The durations of and percentages of time grazing on leaves were similar between sexes. More flies grazed the tops than bottoms of leaves. Flies also grazed on leaves of apple, pear, and grape. The results support the hypothesis that leaf surfaces are the most dependable sources of food for R. indifferens. The tops of leaves may also be the main feeding sites because higher amounts or quality of nutrients occur there than on fruit and fruit are used primarily for mate encounters rather than as feeding sites. Insecticide or bait droplets sprayed on tops of leaves may be highly likely to be found by flies while grazing.