Teratosphaeria pseudoeucalypti, new cryptic species responsible for leaf blight ofEucalyptusin subtropical and tropical Australia

Abstract

Sub‐tropical and tropical plantations ofEucalyptus grandishybrids in eastern Australia have been severely affected by anamorphs ofTeratosphaeria(formerlyKirramyces) causing a serious leaf blight disease. Initially the causal organism in Queensland, Australia, was identified asTeratosphaeria eucalypti, a known leaf parasite of endemicEucalyptusspp. However, some inconsistencies in symptoms, damage and host range suggested that the pathogen in Queensland may be a new species. Isolates ofT. eucalyptifrom throughout its known endemic range, including Queensland and New Zealand, where it is an exotic pathogen, were compared using multiple gene phylogenies. Phylogenetic studies revealed that the species responsible for leaf blight in Queensland represents a new taxon, described here asTeratosphaeria pseudoeucalypti. While the DNA sequence ofT. pseudoeucalyptiwas more similar toT. eucalypti,the symptoms and cultural characteristics resembled that ofT. destructans. The impact of this disease in central Queensland has increased annually and is the major threat to the eucalypt plantation industry in the region.