Observations on Rhagoletis indifferens and related species in the Okanagan Valley of British Columbia

The western cherry fruit fly, <i>Rhagoletis indifferens</i> Curran, was first recorded in the Okanagan Valley of British Columbia in 1968, and trapping during 1969 established the presence of this species in most of the cherry growing districts in the region. <i>R. indifferens</i> emerges as an adult in early June, and flies continue to appear until mid-July. The principal host of this species, <i>Prunus emarginata</i> Dough., was not found in the Okanagan, and no flies were found on <i>Prunus virginiana demissa</i> (Nutt.) which has been reported as a host. A comparison of lures to trap the flies showed that ammonium carbonate traps were more efficient than yellow sticky boards or glycine-lye bait pans. The sticky boards, however, seem to be adequate for determining the presence of cherry fruit flies. In addition to <i>R. indifferens</i>, 5 other <i>Rhagoletis</i> were trapped in commercial cherry orchards. The common species were <i>R. zephyria</i> Snow, <i>R. ribicola</i> Doane, and <i>R. berberis</i> Curran. <i>R. fausta</i> (Osten Sacken) and <i>R. tabellaria</i> (Fitch) were trapped in very low numhers in a relatively few locations