Dalphy Ondine Camira Harteveld
Forsker
Forfattere
Jorunn Børve Theresa Weigl Emily Follett Ingunn Øvsthus H. Larsen Torbjørn Haukås E. Indergård S.F. Remberg Dalphy Ondine Camira Harteveld Arne StensvandSammendrag
Evaluating the effect of different treatments after a simulated shelf life is common in postharvest industry experiments. As fungal fruit decay development is closely linked to preharvest factors, fruit quality, and postharvest treatments two other time points were added in recent experiments. When commercial packinghouses graded the different experimental units (from 1 to 4 bins) they made three different samples; 1) all the fruit manually discarded before size grading (mostly external symptoms of fungal fruit decay and physiological disorders), 2) a 100-fruit sample of the fruit not regarded as first class by the grading machine at size grading (fruit that could be used for industry purpose, processing fruit), and 3) packed fruit for shelf life testing. As expected, differences in pathogen presence were found varying with storage time, cultivar, season, treatments, etc., but overall, some important factors could be pointed at: up to 70% of the processing fruit had damages (caused by insects, weather or mechanical damage) that could be an entry point of fungal pathogens in storage. Apple scab was found on up to 60% of that fruit and up to 12% of the graded fruit in shelf-life tests, indicating a less effective fungicide strategy in some of the commercial orchards. The additional knowledge gained by having three sample types in the experiments is discussed.
Forfattere
Dalphy Ondine Camira Harteveld Abdelhameed Elameen Simo Maduna Adam Vivian-Smith Andrea Podavkova Sabine Oettl Stefanie Maria Primisser Jorunn BørveSammendrag
Small, superficial rot spots occurring around lenticels postharvest on apple in Norway have not been identified but were assumed to be underdeveloped Neofabraea lesions. Fungal isolation from such spots on fruit from the 2022 season revealed both Neofabraea perennans and Ramularia spp., identified by B-tubulin and ITS sequencing, respectively. In the 2023 season, isolations were made from fruit with spots resembling dry lenticel spot caused by Ramularia mali. The aim of this study was to identify the Ramularia species associated with the postharvest fruit spots in Norway. Multiple gene regions of five Norwegian isolates (E20, E21 from 2022; 13,15 and 18 from 2023) and three reference isolates, R. mali, R. eucalypti, and R. collo-cygni, were sequenced and used for phylogenetic analysis. The Norwegian isolates were distinct from the included reference isolates, but clustered with other Ramularia species. Isolates 13, 18 and E21 clustered with Ramularia vizellae, while isolates 15 and E20 were most closely related to Ramularia phacae-frigidae. Isolate E20 was sequenced using the Oxford Nanopore Technologies MinION platform. Pathogenicity was assessed in a field inoculation study using isolate E21, resulting in typical spot development on inoculated fruit. Ramularia vizellae has previously been reported from dead apple leaf litter and other woody hosts in the Netherlands and Iran, while R. phacae-frigidae was originally described from Phaca frigida in Switzerland. Neither species has previously been reported in association with apple fruit spotting. While Ramularia mali has caused outbreaks on apple in several European countries, recent studies hypothesize that the symptoms may be caused by a species complex with regional variation. The present results identify candidate species contributing to this complex in Norway and highlight the need for further studies to improve species delimitation and pathogenicity.
Forfattere
Dalphy Ondine Camira Harteveld Ola Sigurd Øygard Dale Håvard Vedå Vinh Hong Le Jorunn Børve Torfinn Torp Arne StensvandSammendrag
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