Characterization of Neopestalotiopsis species associated with lingonberry (Vaccinium vitis-idaea L.) diseases in Canada

Abstract

Lingonberry (Vaccinium vitis-idaea L.) is a dwarf shrub that is native to Northern climates. The berries are harvested from wild plants and the disease incidence in the crop is generally low. However, disease pressure may increase since the surface area dedicated to the crop is expected to expand in the future. In 2021 and 2022, brown necrotic leaves and stem dieback symptoms were observed on lingonberry plants grown at the St. John’s Research and Development Center, Newfoundland and Labrador, Canada. Pathogens were isolated from the diseased plant tissues and identified as Neopestalotiopsis rosae (n = 2) and Neopestalotiopsis zimbabwana (n = 2) using colony and conidia morphology as well as sequencing of the Internal Transcribed Spacer (ITS), beta-tubulin gene (ß-tub), and the translation elongation factor 1-alpha gene (tef1). Pathogenicity assays in detached lingonberry and strawberry leaves as well as lingonberry plants indicated that all four isolates were able to cause disease. This is the first report of N. rosae and N. zimbabwana causing leaf spot and stem dieback of lingonberry. Further monitoring of this disease is important to understand its prevalence in berry crops, as Neopestalotiopsis spp. in Canada have been reported to occur since 2018 in strawberry and other small fruits. Control measures and strategies are required to mitigate the potential risk from the disease, as there are no registered fungicides available to the growers.