The eucalypt leaf blight pathogenKirramyces destructansdiscovered in Australia

Abstract

Kirramyces destructans is a serious pathogen causing a leaf, bud and shoot blight disease of Eucalyptus species in plantations of the subtropics and tropics of South East Asia. This pathogen was first discovered in Indonesia in 1995 and has subsequently spread to Thailand, China and Vietnam. Kirramyces destructans is not known to occur in Australia and has been considered a major biosecurity threat. During the course of the past four years, surveys have been conducted in existing eucalypt trials in tropical Australia. Several Kirramyces spp. were detected in these surveys, including isolates with morphological and cultural characteristics resembling those of K. destructans. In this study, DNA sequences of three gene regions were used to compare isolates of Kirramyces spp. emerging from the surveys and these were compared with those of K. destructans and the closely related K. eucalypti and K. viscidus. Results have shown, for the first time, that K. destructans is present in northern Australia (Melville Island, Northern Territory and Derby, Western Australia). The observed sequence variation among a small number of isolates also strongly suggests K. destructans is endemic to Northern Australia.