The most severe insect pest of cherries in Europe is the European cherry fruit fly, Rhagoletis cerasi. It has been detected in North America, in Ontario (2016), New York State (2017) and most recently in Quebec (2022). European cherry fruit fly has not been detected in Manitoba, Saskatchewan, Alberta, or British Columbia.
European cherry fruit fly is regulated as a quarantine pest in Canada. If found, it should be reported to the CFIA.
Suitable host plants of European cherry fruit fly include sour cherry, sweet cherry, and black cherry, as well as honeysuckle and some ornamental cherry species. In the United States, it has been found on barberry, coralberry, dogwood and snowberry.
Adult European cherry fruit flies are typically active between May and July. Female flies lay eggs into suitable host fruits, under the skin. Larvae develop feeding inside the fruit, resulting in unappetizing fruit for human consumption. Larvae drop to the soil to pupate and overwinter in the pupal stage, which can last up to 3 winters.
Adult flies are quite small and can be hard to detect. Cherries and other fruits that have been infested usually have areas of rotten or spoiling flesh around the oviposition site. When cut open, fruits infested with European cherry fruit fly can be identified by characteristic tunneling, resulting from larval feeding.
For more information and pictures of European cherry fruit fly please check out this CFIA factsheet or this article prepared by the Invasive Species Centre.