|Goughnour, Robert - Washington State University Extension Service|
Submitted to: Pan-Pacific Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/13/2016
Publication Date: 12/28/2016
Citation: Yee, W.L., Goughnour, R.B. 2016. Peach is an occasional host for Rhagoletis pomonella (Walsh, 1867) (Diptera: Tephritidae) larvae in Western Washington State, USA. Pan-Pacific Entomologist. 92(4):189-199.
Interpretive Summary: The apple maggot fly is a major quarantine pest of commercial apple in the Pacific Northwest of the U.S., but the fly also reportedly attacks peach, another economically important fruit. However, all reports of peach as a host appear erroneous. Personnel at the USDA-ARS Yakima Agricultural Research Laboratory in Wapato, WA, and Washington State University in Vancouver, WA tested the hypothesis that apple maggot does not utilize peaches in western Washington state by collecting commercial peaches near unmanaged apple-maggot infested apple trees in Vancouver, WA. No apple maggot larvae were reared from peaches collected in 2013 and 2014, but 24 larvae were reared from peaches in 2015. Results are important because they suggest unmanaged apple trees near commercial peach orchards should be treated to reduce the chances of maggots infesting peaches.
Technical Abstract: Peach, Prunus persica (L.) Batsch (Rosaceae), has been reported to be a host of the apple maggot fly, Rhagoletis pomonella (Walsh), 1867 (Diptera: Tephritidae), an important quarantine pest of apple (Malus domestica Borkhausen) (Rosaceae) in the western U.S.A. However, all reports of peach as a host appear erroneous. Here, we tested the hypothesis that apple maggot does not utilize peaches in western Washington state. In 2013, unbaited sticky yellow rectangle traps were hung in an insecticide-managed peach orchard ~50 m from neglected apple trees in Vancouver, Washington. During 2013–2015, peaches in the orchard were collected, peaches were hung in infested apple trees, and peaches were exposed to flies in the laboratory. In 2013, 24 flies were caught on 200 traps in the peach orchard, but no larvae were reared from 4,243 ‘Alberta’ or ‘Redhaven’ peaches collected under ~200 trees in 2013 and 2014 or from peaches hung in apple trees in 2013. In 2015, however, 24 apple maggot larvae were reared from 804 ‘Starfire’ or ‘PF 23’ peaches, specifically from collections under two of 13 trees. In addition, in one of four laboratory tests, 11 total larvae were reared from ‘Redhaven’ peaches exposed to apple maggot flies. Contrary to our prediction, results definitively show that peach can be an occasional developmental host for apple maggot under field and laboratory conditions.