First Report of Blast Disease on Hymenachne amplexicaulis Caused by Pyricularia oryzae in Argentina

In 2022, blast- like symptoms were observed on Hymenachne amplexicaulis plants in Argentina. The causal agent was identified as Pyricularia oryzae based on its cultural and morphometric characteristics, sequencing of the ITS1–5.8S–ITS2 region, phylogenetic analysis, and PCR amplification of the Pot2 transposon marker. Koch's postulates were fulfilled through pathogenicity tests on both H. amplexicaulis and Oryza sativa cv. Guri INTA CL, placing the isolate within a clade that includes P. oryzae strains known to infect Oryza spp. The ITS sequence was deposited in GenBank under accession number OR741771. To the best of our knowledge, this is the first report worldwide of H. amplexicaulis serving as a host for P. oryzae.