Asiatic citrus canker (ACC), caused by Xanthomonas citri pv. citri, is a threat to citrus industries worldwide. X. citri pv. citri is delineated into three pathotypes differing in pathogenicity towards Citrus species and hybrids. The pathogen negatively impacts production in tropical and subtropical areas, resulting in direct losses (yield decrease due to premature fruit drop and/or defoliation, alteration of fruit quality, and increased production costs) and indirect losses (Graham et al. 2004). Several surveys on various citrus pests and pathogens have been conducted in Madagascar over the last two decades, with no signs of Asiatic canker at any time or place. Typical canker-like symptoms were first observed in May 2024 in a single site of the Boeny region of Madagascar, with low incidence and severity. Bacterial isolation and identification were performed according to the protocols described in EPPO standard PM7/44(2) (EPPO 2023). Three strains were purified and further characterized (LW023-1, LW023-2 and LW023-3). Unlike the negative control (sterile 0.01M Tris buffer, pH 7.2), all three strains, along with strain IAPAR306 (positive control), produced typical XAC1051 amplicons by real-time PCR (EPPO 2023). Based on MLVA-31, which targets 31 minisatellites, Madagascar strains were assigned to lineage one, composed of pathotype A strains (Pruvost et al. 2014). All strains were inoculated onto Mexican lime (C. x aurantiifolia) SRA 140 and sweet orange 'Washington Navel' SRA 102 (C. x sinensis). Inoculations consisted of infiltrations of bacterial suspensions (three replicates each consisting of eight infiltrations) containing approximately 1 x 105 cells/mL in Tris buffer. Plants were incubated at 30°C during the day and 26 °C at night, with a 12/12-hour light/dark cycle and a relative humidity of approximately 80%. All inoculated leaves but the negative control produced typical erumpent, canker-like lesions at inoculation sites on both citrus species six to seven d