Resistance to the pandemic strain of Austropuccinia psidii was identified in New Zealand provenance Leptospermum scoparium, Kunzea robusta, and K. linearis plants. Only 1 Metrosideros excelsa-resistant plant was found (of the 570 tested) and no resistant plants of either Lophomyrtus bullata or L. obcordata were found. Three types of resistance were identified in Leptospermum scoparium. The first two, a putative immune response and a hypersensitive response, are leaf resistance mechanisms found in other myrtaceous species while on the lateral and main stems a putative immune stem resistance was also observed. Both leaf and stem infection were found on K. robusta and K. linearis plants as well as branch tip dieback that developed on almost 50% of the plants. L. scoparium, K. robusta, and K. linearis are the first myrtaceous species where consistent infection of stems has been observed in artificial inoculation trials. This new finding and the first observation of significant branch tip dieback of plants of the two Kunzea spp. resulted in the development of two new myrtle rust disease severity assessment scales. Significant seed family and provenance effects were found in L. scoparium, K. robusta, and K. linearis: some families produced significantly more plants with leaf, stem, and (in Kunzea spp.) branch tip dieback resistance, and provenances provided different percentages of resistant families and plants. The distribution of the disease symptoms on plants from the same seed family, and between plants from different seed families, suggested that the leaf, stem, and branch tip dieback resistances were the result of independent disease resistance mechanisms.

Myrtle rust, caused by the pathogen Puccinia psidii, is a disease of plants in the Myrtaceae that is currently not known to be present in New Zealand. Its origin is Central/ South America, but it has steadily spread around the world and is now found in Australia. All New Zealand Myrtaceae species, including indigenous species, are at risk from myrtle rust infection, but the extent of the impact on plant health is not known. While the potential economic and environmental impacts of myrtle rust establishment in New Zealand have been well documented, this paper explores potential socio-cultural consequences for Māori. All indigenous Myrtaceae species can be considered as taonga (or treasure) by Māori, who have and continue to use the properties of some species in many ways (both tangible and intangible). Preparedness and response plans for a myrtle rust incursion in New Zealand should consider the values that Māori derive from these plants.

The incursion of the myrtle rust disease (Austropuccinia psidii) was officially confirmed on 3 May 2017 at a plant nursery located in Kerikeri, North Island, New Zealand. Since then the presence of myrtle rust has now been located throughout New Zealand, with additional outbreaks in Taranaki, Waikato and Bay of Plenty. It has been detected on a range of Myrtaceaea species including ramarama (Lophomyrtus bullata), pōhutukawa (Metrosideros excelsa), Monkey apple (Syzygium smithii), mānuka (Leptospermum scoparium), and Eucalyptus spp. (E. botryoides). Many of these species are iconic to the Indigenous Māori and have historical significance, being taonga (treasures). Since the incursions, Te Tira Whakamātaki (National Māori Biosecurity Network), have been informing Māori communities throughout New Zealand about the potential impacts of myrtle rust via a series of regional meetings (hui), email and social media that have included brief reports and recommendations. Feedback from these meetings and social media has strongly highlighted the desires of Māori communities to be active participants in decision-making and response plans for the management of myrtle rust as well as other pests and diseases. In this paper, we describe the journey of an Indigenous community approach to a modern biosecurity incursion.

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Current forest biosecurity systems and processes employed in many countries are, in large, constructs of Western principles, values and science knowledge that have been introduced and integrated internationally. They are often devoid of knowledge, and of the values and principles, held by indigenous people, even those who have an intimate and enduring relationship with their forests. Indigenous people are also often overlooked in policy and decision-making processes, yet are often most affected by biosecurity pests and pathogens that impact native plant species that they may rely on for sustenance, cultural or spiritual purposes. By adopting an inclusive approach, scientists and indigenous people can achieve more comprehensive and robust biosecurity outcomes through a shared diversity of knowledge and at the same time serves to elevate and recognise the importance of indigenous knowledge. A co-innovation approach can also result in more widespread adoption of tools or practices by end-users including indigenous people. Understanding New Zealand Māori and their unique knowledge base can help improve forest biosecurity systems and practices, as can discussions of barriers that can and have prevented adoption of inclusiveness. Here we outline key principles behind indigenous engagement, specifically the need to develop enduring relationships.