Host, Pathogen & Environment

Looking into the role environmental factors play on disease expression and severity, as well as investigating plant pathogen genomes.

At A Glance:

Trees infected with kauri dieback and myrtle rust do not grow in isolation. The trees and diseases can both be influenced by a number of factors such as disturbance, topography, weather, soil type and pest control. These factors can, in turn, affect how the plant pathogens adapt to the New Zealand environment.

This investment team will look into the role environmental factors play on disease expression and severity, as well as investigating the pathogen genomes. The knowledge gained will contribute to improving surveillance, control, management and conservation efforts, and we hope to discover new ways to mediate these diseases.


Juliane Chetham

Patuharakeke, Ngātiwai, Ngāpuhi

Chetham Consulting Ltd.

Dr Beccy Ganley

Plant & Food Research


Connecting with key mana whenua/kaitiaki either already involved in this research or with relevant skills is underway, as well as linking to other themes to design mātauranga Māori led projects and embed it across the research. Hui/meetings have also just started. The plan is to establish research teams across the following areas:

  1. Pathogen genetic diversity (Phytophthora agathidicida and Austropuccinia psidii)
  2. Influence of biotic and abiotic stressors on (a) disease latency and expression, and (b) host responses
  3. Environmental biological drivers of kauri dieback, in particular the influence of other Phytophthora
  4. Pathogen genome investigation (Phytophthora agathidicida and Austropuccinia psidii)
  5. Myrtaceae genome investigation (for example, mānuka & eucalypt)

Other work already well underway includes two areas of myrtle rust field work that have been undertaken under urgency during the current “myrtle rust season”. That is, the months during which myrtle rust infection is most common – approximately October to April.

This collaborative research, being undertaken by researchers from Plant & Food and Scion, includes:

1. Monitoring the impact of myrtle rust on native Myrtaceae, especially highly vulnerable Lophomyrtus species

This project is led by Roanne Sutherland (Scion) in Rotorua and continues the monitoring of natural myrtle rust spread. This knowledge is essential to knowing how the disease might develop in Aotearoa.

Infected trees and others surrounding them are surveyed every two weeks for disease severity and occurrence. Seedling plots are surveyed to monitor survival rate and infected fruits are monitored to see if they can still produce seedlings.

2. Measuring leaf flush (new growth) in native Myrtaceae

Led by Dr Robert Beresford (Plant and Food Research), this research is collecting information about the time period plant species are susceptible to myrtle rust.

The data will inform predictive surveillance models and is being carried out in conjunction with Project 1.

Upcoming Activities:

  • Monitoring of field sites for the myrtle rust projects will continue until at least July 2020 (subject to Covid-19 restrictions), at which time these projects will merge with others under the ‘Host, Pathogen & Environment’ research theme.
  • Co-develop a plan for research into the interaction between host, pathogen and the environment

Updated May 2020

Research Partners

Plant & Food Research


Chetham Consulting Ltd.


Find out more about myrtle rust research  in Aotearoa:

Myrtle rust in NZ

Beyond Myrtle Rust

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