Myrtle Rust Continues to Blight Subtropical Rainforest Trees: Strategies for Resurrecting the Living Dead

ABSTRACT Following identification of rainforest tree species at imminent risk of extinction from the myrtle rust disease in Australia further field data is presented to provide an update of impacts. A recently described species Rhodamnia zombi is added to the list of 16 species classified as Category X, that is, potentially Critically Endangered according to Red Listing criteria as a result of decline from the impacts of myrtle rust. Monitoring data demonstrates that one of the last remaining wild populations of Rhodomyrtus psidioides of mature trees has collapsed. One of three suspected clonal clumps of Rhodamnia rubescens has declined and another two survive despite evidence of the disease on new growth. A conservation strategy to recover Category X species involves: (1) Searching for and propagating individuals from the wild displaying tolerance; (2) Establishing plants in sites where they are safe from myrtle rust; (3) Undergoing genetic analysis to ensure wild diversity is represented; (4) Maintaining plants to produce seed; (5) Nursery screening of seedlings for myrtle rust resistant genotypes; (6) Screening field plantings for verification of resistant genotypes; (7) Rewilding resistant strains; Examples of successful ex situ cultivation in myrtle rust free settings or with fungicide application are collated and engender hope that this intensive strategy can succeed.