Timing, magnitude and causes of flower and immature fruit loss in pin cherry and choke cherry

Abstract

Pin cherry (Prunus pensylvanica L.) and choke cherry (Prunus virginiana L.) are two wild fruit species with potential for commercial production, but information about fruit production is limited. The objectives of this study were to determine, for both species, the timing and magnitude of flower and immature fruit loss, and to determine the primary causes of this loss, including the effects of pollen source and supplemental pollination. Sequential sampling of both pin cherry and choke cherry indicated that the primary period of abscission occurred during the first 3 wk following full bloom. Final fruit set ranged from 32.6 to 44.7% of flower number for pin cherry, and from 3.7 to 20.1% for choke cherry. Insect damage accounted for only 14% of the total observed flower and fruit abscissions in pin cherry and 7% in choke cherry. The major insect pest causing this loss in pin cherry was a sawfly (Hoplocampasp., Tenthredinidae) and in choke cherry, a leaf-roller (Archips argyrospila, Tortricidae). A controlled pollination experiment was used to determine the effects of pollen source and supplemental pollination on pin cherry and choke cherry. Final fruit set for flowers that were cross-pollinated by hand in both pin cherry (mean of 51.3%) and choke cherry (mean of 56.9%) in most cases was significantly greater than flowers that were open-pollinated, self-pollinated, or not pollinated. These data suggested that the majority of flower and immature fruit loss in both pin cherry and choke cherry resulted from a lack of pollination and/or fertilization. Key words: Choke cherry, pin cherry, flower loss, immature fruit loss, pollination, insect damage