Discovery of Botryosphaeria eucalypti sp. nov. from blighted Eucalyptus leaves in India

Eucalyptus spp. are undoubtedly one of the most favored plantation trees globally. Accurately identifying Eucalyptus pathogens is therefore crucial for timely disease prevention and control. Recently, symptoms of a leaf blight disease were observed on Eucalyptus trees in plantations at Jhajjar and Karnal in the state of Haryana, northern India. Asexual morphs resembling the features of the Botryosphaeriaceae were consistently isolated from the symptomatic leaves. Morphological features coupled with DNA sequence analysis confirmed a novel species, which is described and illustrated here as Botryosphaeria eucalypti sp. nov. Conidia of the new taxon are longer and wider than those of its phylogenetic neighbors. A distinct phylogenetic position for the new taxon was established through combined analysis of the internal transcribed spacer (ITS), partial translation elongation factor-1α (tef1) and partial β-tubulin (tub2) regions. Recombination analysis provided additional support for the new species hypothesis. The pathogenicity of the novel species was proved on Eucalyptus leaves, and Koch's postulates were fulfilled. The discovery of new Botryosphaeria species is important because it will help in understanding the species diversity, host range, possible threats and disease control in the long run.