Neofusicoccum eucalyptorum, a Eucalyptus pathogen, on native Myrtaceae in Uruguay

Abstract

Neofusicoccum eucalyptorum is a canker‐associated fungus apparently highly specialized on Eucalyptus. However, in surveys of the microbial population inhabiting native Myrtaceae in Uruguay, fungal cultures resembling N. eucalyptorum were isolated. The possible occurrence of N. eucalyptorum on hosts other than Eucalyptus prompted further investigation. Several surveys were conducted throughout Uruguay to obtain samples from native forests, focusing primarily on species in the Myrtaceae. Fungal identification was based on morphology and confirmed using comparison sequences for the internal transcribed spacer (ITS) of the rDNA operon. Pathogenicity was evaluated by inoculating plants of a Eucalyptus grandis clone. Morphological and molecular identification confirmed the occurrence of N. eucalyptorum on Blepharocalyx salicifolius, Myrceugenia glaucescens and Myrrhinium atropurpureum var. octandrum. This is the first report of N. eucalyptorum occurring in hosts other than Eucalyptus. Pathogenicity tests confirmed the ability of this species to produce cankers on E. grandis. This study provides information that will assist breeding programmes in attempts to obtain disease‐resistant Eucalyptus plantations and it also suggests that a Eucalyptus pathogen could have moved to native trees in Uruguay.