The European cherry fruit fly has great economic importance in Poland and all over the world. The infestation of sweet cherry fruits by its larvae can reach 100%. The aim of the study was to compare the levels of infestation of a wild cherry, as well as the sweet cherry cultivars ‘Vanda’, ‘Summit’ and ‘Alex’ growing in a chemically controlled orchard, and the cultivar ‘Regina’ in an ecological orchard. The abandonment of chemical control in part of the orchard led to a high level of fruit infestation on unprotected trees. Fruit damage on the late ripening cultivar ‘Alex’ was 45%, while on the ‘Regina’, from the ecological orchard, it was 52%. The percentage of infested fruits was similar regardless of the part of the tree crown (bottom, middle or upper) from which the fruits were sampled. The fruit ripening time of the cultivars had a signifi cant impact on the levels of fruit infestation. Late ripening cultivars were infested to a higher degree than mid-ripening cultivars, which is in accordance with the previous observations of other authors. No parasitoids of Rhagoletis cerasi larvae were found in either stand. This also refers to the stand of wild cherry, in which the occurrence of the parasitoid Psytallia carinata had been noted in the previous year. This research should be continued in more stands, including also the parasitic wasps of R. cerasi pupae.