Myrtle rust (Austropuccinia psidii) has been established in Australia since 2010 and the long-term management story is one of slow but consistent learning. Mid-2026 brings a useful moment to take stock of where the disease pressure sits across the continent, which host species are showing the most concerning trajectories, and what the management research is delivering.

A pragmatic summary based on the most recent surveillance data and the published research outputs through Q1 2026.

The current distribution picture

Myrtle rust is now confirmed across the entire Australian Myrtaceae range. The disease pressure varies substantially by ecoregion and by host species, with the highest impact in subtropical and warm temperate zones along the east coast, moderating in the cooler southern parts of the range and the drier inland regions.

The northward expansion into the Cape York and tropical north has been documented but the disease pressure in these regions appears lower than in the originally-affected ranges. The western expansion through Western Australia has been slower than initial models suggested, reflecting both the climatic constraints and the disjointed Myrtaceae distribution in WA’s south-west.

The Tasmanian situation continues to be carefully monitored. Surveillance has detected the pathogen in several locations but the impact on the Tasmanian Myrtaceae has remained limited so far. Whether this is a function of climate, host genetic resistance, or simply time-to-establishment is an active research question.

Host species with the most concerning trajectories

The host-specific impacts continue to be highly variable. The species showing the most concerning long-term trajectories include:

Native guava (Rhodomyrtus psidioides). The species has effectively been functionally extirpated from much of its historical range. Conservation collections in botanic gardens and ex-situ programs are now the primary refugia.

Several Eucalyptus species in the broader-leaved subgenus. Specifically, certain species in the Eucalyptus Section Latoangulatae are showing chronic disease pressure that’s affecting reproductive success and seedling recruitment. The long-term population trajectories will depend on whether resistance emerges in the host populations.

Backhousia, Syzygium and several rainforest understorey Myrtaceae. The disease pressure is concentrated in the seedling and juvenile stages, with adult trees often persisting but their reproductive success compromised.

Several Leptospermum species. Including some that are commercially important for honey production. The disease pressure varies by species, with some heavily affected and others showing more resistance.

Where the research is making headway

A few research programs that have delivered useful outcomes through 2024-2026.

Resistance screening programs. Several Australian research institutions have built substantial resistance screening pipelines, identifying individuals within affected host populations that show meaningful resistance to local myrtle rust strains. The conservation implication is significant — building seed orchards and conservation plantings around identified resistant material gives several at-risk species a credible long-term future.

Strain monitoring. The diversity of myrtle rust strains present in Australia has been characterised more completely. Current evidence suggests the Australian population is descended from a relatively small number of original introductions, with limited subsequent diversity. This is good news from a management perspective — it means resistance breeding programs can target a more uniform pathogen population.

Biocontrol research. Several biocontrol candidates have been evaluated through 2024-2026. None has yet been advanced to large-scale field release but the evidence base for future deployment has been strengthened.

Cultural and silvicultural management. Research into stand-level and landscape-level practices that reduce myrtle rust impact has produced useful outcomes for both production forestry and conservation management. Specific practices around planting density, species mixing, and stand age structure can meaningfully reduce disease impact in managed Myrtaceae stands.

Implications for nursery and landscape sectors

For the commercial nursery sector, myrtle rust management remains a routine operational discipline:

Hygiene practices in nursery production are well-established. Glasshouse hygiene, propagation tool sterilisation, stock-plant management, and produce isolation are all routine for nurseries propagating Myrtaceae.

Fungicide programs for nursery production are mature, with rotation strategies between active ingredients to manage resistance. The Australian Pesticides and Veterinary Medicines Authority has maintained registrations for the key actives.

Cultivar selection has shifted toward varieties demonstrating field tolerance. Several commercial Myrtaceae lines have been replaced or supplemented with more tolerant alternatives, particularly in the landscape and ornamental segments.

The bigger ongoing challenge is the home garden sector, where management discipline is less reliable and where myrtle rust spread can occur through poor sanitation. Public education programs have continued but the diffuse nature of the home garden environment makes consistent management difficult.

Conservation implications

The conservation implications of myrtle rust continue to drive significant adjustment in the Australian biodiversity management framework.

Several species are now listed as threatened specifically because of myrtle rust impact. The recovery plans for these species have been developed and are progressively being implemented.

The ex-situ conservation networks — botanic gardens, seed banks, university collections — are carrying a meaningful share of the survival burden for the most affected species. The coordination between these institutions has improved through 2024-2026 with the formal recognition of the importance of ex-situ work.

The long-term in-situ conservation strategy depends substantially on whether resistance can be built into wild populations and whether the disease pressure stabilises at a level that allows host population recovery. The honest answer in mid-2026 is that this remains uncertain for several species, and the conservation effort needs to maintain both ex-situ and in-situ workstreams.

The myrtle rust story in Australia is a useful case study in long-term biosecurity outcomes. The disease wasn’t eradicated. The early containment efforts didn’t succeed. But the long-term adjustment — through research, through management practice, through conservation programming — has been substantial and has prevented the worst-case outcomes that some early modelling suggested. The work continues, and the results in 2030 will reflect choices being made today.