Résumé
The Grand Est region is the leading French region for the production of damson (Prunus domesticasubsp. insititia) and mirabelle (Prunus domestica subsp. syriaca) plums. Damson production isthreatened by sharka, caused by the plum pox virus (PPV) spreading in this region, and controlmeasures based on visual inspection and removal of symptomatic trees are implemented inorchards. In contrast, only very few symptoms have been reported on mirabelle leaves and fruits.Therefore, sharka is generally not surveyed on this species, despite the lack of scientific evidence onthe susceptibility of mirabelle to the main PPV strains (M, D and Rec) and on its potential role insharka epidemics occurring in the Grand Est region.We combined orchard surveys with experimental assays under controlled conditions to (i) estimatePPV prevalence in mirabelle orchards and (ii) evaluate the susceptibility of two mirabelle cultivars(P1725 and P1510) to PPV-M, PPV-D and PPV-Rec isolates after graft- and aphid-inoculation incomparison with a susceptible damson cultivar (P3066).PPV presence was assessed by DAS-ELISA in 7102 leaf samples collected from 4481 trees in 53mirabelle orchards. PPV was detected in 15% of the orchards, but the overall prevalence was verylow (1.7%). The virus was detected mainly in rootstock suckers (2.6%) and occasionally inasymptomatic mirabelle leaves (0.25%).Experiments showed that both of the tested mirabelle cultivars were susceptible to the three mainPPV strains regardless of the inoculation method, with typical PPV symptoms on leaves. Keyparameters of the infection cycle (transmission rate to test plants, incubation period, viral load, andretransmission rates by aphids from PPV-infected plants) showed that the susceptibility of themirabelle cultivars is lower than that of the damson cultivar and depends on the PPV strain. Apparentdiscrepancies between survey and experimental results are discussed