Pseudoplagiostoma eucalypti: An emerging pathogen of Eucalyptus in northern India

In December 2022, a leaf spot and blight disease was observed in Eucalyptus plantations in northern India. Morphological features coupled with phylogenetic analysis of combined internal transcribed spacer (ITS), translation elongation factor 1-alpha (tef1) and beta-tubulin (tub2) regions confirmed the association of Pseudoplagiostoma eucalypti with the disease symptoms. The pathogenicity of P. eucalypti was first proved on detached leaves of Eucalyptus camaldulensis and reconfirmed in glasshouse inoculation experiments. Finally, Koch's postulates were fulfilled by re-isolating the pathogen from the inoculated leaves. This pathogen was first described in 1995 from the leaves of Eucalyptus spp. collected from southern India, and this study confirms its first serious occurrence after more than two decades in northern India. In addition, this is the first report on the polyphasic characterization of P. eucalypti from India.