Invasive Plant Pathogens Research Articles

Environmental drivers of spatial variation in myrtle rust development on a critically endangered tree species

The spread of invasive plant pathogens is on the rise globally, introducing additional threats to forest ecosystems and their constituent species above those already caused by climate change and other anthropogenic stressors. Austropuccinia psidii is a widespread invasive fungus that infects hundreds of species in the Myrtaceae plant family, causing myrtle rust. It was first detected in New Zealand in 2017, where the threatened endemic tree Lophomyrtus bullata is one of the worst affected hosts. Recent studies have described heavy disease severity on this species but environmental drivers of spatial variation in disease severity have not been explored, including the possible role of edge effects which are prevalent across much of this species' highly fragmented natural range. In this study, we tracked changes in disease incidence and severity across a forest edge gradient over three years. Individuals further from the forest edge, where forest canopies were more intact, forest structure more complex, and with greater understorey humidity, had greater disease severity in the first year of infection. In subsequent years, the influence of edge was no longer evident as myrtle rust severity became more even across the site, but disease was more prevalent in denser L. bullata populations. Only small individuals were asymptomatic across all three years. Since all available myrtle rust control techniques are currently feasible only at small scales, our research implies that their application needs to be as early as possible before infection spreads and across all suitable microclimates, and without bias toward easily accessible forest edges.

LAMP Reaction in Plant Disease Surveillance: Applications, Challenges, and Future Perspectives

Movements of plant pathogenic microorganisms in uncontaminated areas occur today at an alarming rate, driven mainly by global trade and climate change. These invaders can trigger new disease outbreaks able to impact the biodiversity and economies of vast territories and affect a variety of ecosystem services. National and supranational regulatory deficiencies, such as inadequate quarantine measures and ineffective early pathogen detection at ports of entry, exacerbate the issue. Thus, there is an urgent need for accurate and rapid diagnostic tools to intercept invasive and nonindigenous plant pathogens. The LAMP (Loop-mediated isothermal AMPlification) technique is a robust, flexible tool representing a significant advance in point-of-care (POC) diagnostics. Its user-friendliness and sensitivity offer a breakthrough in phytosanitary checks at points of entry (harbors and airports), for disease and pest surveillance at vulnerable sites (e.g., nurseries and wood-processing and storage facilities), and for territorial monitoring of new disease outbreaks. This review highlights the strengths and weaknesses of LAMP, emphasizing its potential to revolutionize modern plant disease diagnostics.

The vector regulation hypothesis: dynamic competition between pathogen and vector behaviors constrains Xylella fastidiosa biofilm development in sharpshooter foreguts.

Xylella fastidiosa (Xf) bacteria form biofilm on the cuticular surfaces of the functional foregut (precibarium and cibarium) of its vectors, xylem fluid-ingesting sharpshooter leafhoppers and spittlebugs. While much is known about Xf biofilm development and maturation in vitro, little is known about these processes in vectors. Real-time (RT)-PCR was used to quantify Xf genomes daily in the functional foreguts of blue-green sharpshooters, Graphocephala atropunctata, over 7 days of exposure to infected grapevines. Scanning electron microscopy (SEM) was used to examine Xf biofilm formation at 4 and 7 days of that time course. PCR showed populations building and reducing over a 4-day cycle. SEM revealed that foreguts at 4 days showed variability in quantity and location of bacterial attachment. Only early-stage biofilm formation occurred in low-turbulence areas of the cibarium, while high-turbulence areas of the cibarium and precibarium had rare but older, more developed macro-colonies. Biofilm was almost absent at 7 days but left behind adhesive material and remnants of prior colonization. Evidence supports the hypothesis that bacterial colonization was repeatedly interrupted and constrained by the vector. Behaviors such as egestion and enzymatic salivation likely can loosen and eject Xf biofilm, perhaps when profuse biofilm interferes with ingestion. Thus, vector acquisition of Xf is a dynamic and stochastic process of interactions between bacteria and insects. We further hypothesize for future testing that the insect can regulate this interaction. A deep understanding of Xf acquisition will aid the ongoing development of grapevine resistance to vector transmission of xylellae diseases.IMPORTANCEXylella fastidiosa (Xf) is one of the most destructive invasive plant pathogens in the world, able to hijack new vectors when it invades a region; yet the temporal interplay of bacterial colonization and insect behavior is unknown. This paper describes important findings about the process of Xf biofilm formation and maturation in a vector, contrasting similarities and differences with such formation in vitro. Results support the hypothesis that the behavior of the vector constrains and may regulate Xf biofilm formation, in dynamic competition with the bacterium. The data from this paper partly explain why Xf is so successful at invasion. Because the bacterium can be acquired and inoculated very quickly, it can move readily from old to new vectors and host plants in all-new environments. Our findings are relevant to biosecurity decisions because they demonstrate the importance of identifying potential vector species in the Xylella invasion front.

Modelling the front dynamics of invasive plant pathogens through the analysis of spatial gradients

Variables of phytopathological interest correlated to the impact of plant diseases, such as incidence and severity, may display a spatial pattern resulting from an underlying, yet unknown gradient. Along the main direction of the gradient the variable assessed at the site level either increases, or decreases. Spatial gradients may also arise because of the movement of a front of invasion, an imaginary moving contour separating areas already infested by a plant pathogen from those still pathogen-free. Adequate geostatistical tools may shed light on gradients directional properties, as well as on the direction the front of invasion is coming from or moving to. Tools currently available for that may be impractical due to the advanced computational and programming skills required for their application. Hence, the goals of this study were: (I) to develop, test and validate a new user-friendly geostatistical tool named DirGrad (Direction of Gradient) aimed at analyzing spatial gradients resulting from the impact of plant diseases; (II) to build an algorithm able to run DirGrad on R, one the most widespread open source software for statistics; and (III) to apply DirGrad for the ex post modelling of the invasion front dynamics. The designed algorithm was successfully validated both in silico and in the field by using data from real case studies such as those of the invasive fungal pathogens Heterobasidion irregulare and Ophiostoma novo-ulmi in a forest stand of Central Italy and across the Swedish island of Gotland, respectively. The algorithm is released as a user-friendly open-source script.

Conservation threats from tourism land grabs and greenwash

We report a new threat to conservation, namely land grabs by large tourism developers inside public protected areas. Locally, these tourism land grabs damage national parks through building footprints and access corridors, bringing habitat fragmentation, noise, light, roadkill, fire risk, and invasive plant and animal species and pathogens. They also create negative impacts on social equity and regional economies. The global tourism industry now perceives private development in public national parks as a mechanism to profit from land speculation, rather than merely monopoly provision of visitor services. Investment funds now use tourism, often with socialwashing components, as a political lever for land grabs. International “nature positive” marketing by tourism industry associations and multilateral tourism advocacy organisations is greenwash: it lacks substance, and aims to coopt conservation organisations.

The impacts of ecological disturbances on the diversity of biosynthetic gene clusters in kauri (Agathis australis) soil

BackgroundThe ancient kauri (Agathis australis) dominated forests of Aotearoa New Zealand are under threat from a multitude of ecological disturbances such as forest fragmentation, biodiversity loss, climate change, and the spread of the virulent soil pathogen Phytophthora agathidicida. Taking a wider ecosystem-level approach, our research aimed to explore the impacts of forest disturbance and disease outbreaks on the biosynthetic potential and taxonomic diversity of the kauri soil microbiome. We explored the diversity of secondary metabolite biosynthetic gene clusters (BGCs) in soils from a range of kauri forests that varied according to historical disturbance and dieback expression. To characterise the diversity of microbial BGCs, we targeted the non-ribosomal peptide synthetase (NRPS) and polyketide synthetase (PKS) gene regions for sequencing using long-read PacBio® HiFi sequencing. Furthermore, the soil bacterial and fungal communities of each forest were characterized using 16 S rRNA and ITS gene region sequencing.ResultsWe identified a diverse array of naturally occurring microbial BGCs in the kauri forest soils, which may offer promising targets for the exploration of secondary metabolites with anti-microbial activity against P. agathidicida. We detected differences in the number and diversity of microbial BGCs according to forest disturbance history. Notably, soils associated with the most undisturbed kauri forest had a higher number and diversity of microbial NRPS-type BGCs, which may serve as a potential indicator of natural levels of microbiome resistance to pathogen invasion.ConclusionsBy linking patterns in microbial biosynthetic diversity to forest disturbance history, this research highlights the need for us to consider the influence of ecological disturbances in potentially predisposing forests to disease by impacting the wider health of forest soil ecosystems. Furthermore, by identifying the range of microbial BGCs present at a naturally high abundance in kauri soils, this research contributes to the future discovery of natural microbial compounds that may potentially enhance the disease resilience of kauri forests. The methodological approaches used in this study highlight the value of moving beyond a taxonomic lens when examining the response of microbial communities to ecosystem disturbance and the need to develop more functional measures of microbial community resilience to invasive plant pathogens.

Plant immune receptors interact with hemibiotrophic pathogens to activate plant immunity.

Phytopathogens pose a devastating threat to the productivity and yield of crops by causing destructive plant diseases in natural and agricultural environments. Hemibiotrophic pathogens have a variable-length biotrophic phase before turning to necrosis and are among the most invasive plant pathogens. Plant resistance to hemibiotrophic pathogens relies mainly on the activation of innate immune responses. These responses are typically initiated after the plant plasma membrane and various plant immune receptors detect immunogenic signals associated with pathogen infection. Hemibiotrophic pathogens evade pathogen-triggered immunity by masking themselves in an arms race while also enhancing or manipulating other receptors to promote virulence. However, our understanding of plant immune defenses against hemibiotrophic pathogens is highly limited due to the intricate infection mechanisms. In this review, we summarize the strategies that different hemibiotrophic pathogens interact with host immune receptors to activate plant immunity. We also discuss the significant role of the plasma membrane in plant immune responses, as well as the current obstacles and potential future research directions in this field. This will enable a more comprehensive understanding of the pathogenicity of hemibiotrophic pathogens and how distinct plant immune receptors oppose them, delivering valuable data for the prevention and management of plant diseases.

Bayesian inference for spatio-temporal stochastic transmission of plant disease in the presence of roguing: A case study to characterise the dispersal of Flavescence dorée.

Estimating the distance at which pathogens disperse from one season to the next is crucial for designing efficient control strategies for invasive plant pathogens and a major milestone in the reduction of pesticide use in agriculture. However, we still lack such estimates for many diseases, especially for insect-vectored pathogens, such as Flavescence dorée (FD). FD is a quarantine disease threatening European vineyards. Its management is based on mandatory insecticide treatments and the removal of infected plants identified during annual surveys. This paper introduces a general statistical framework to model the epidemiological dynamics of FD in a mechanistic manner that can take into account missing hosts in surveyed fields (resulting from infected plant removals). We parameterized the model using Markov chain Monte Carlo (MCMC) and data augmentation from surveillance data gathered in Bordeaux vineyards. The data mainly consist of two snapshot maps of the infectious status of all the plants in three adjacent fields during two consecutive years. We demonstrate that heavy-tailed dispersal kernels best fit the spread of FD and that on average, 50% (resp. 80%) of new infection occurs within 10.5 m (resp. 22.2 m) of the source plant. These values are in agreement with estimates of the flying capacity of Scaphoideus titanus, the leafhopper vector of FD, reported in the literature using mark-capture techniques. Simulations of simple removal scenarios using the fitted model suggest that cryptic infection hampered FD management. Future efforts should explore whether strategies relying on reactive host removal can improve FD management.

Using 'sentinel' plants to improve early detection of invasive plant pathogens.

Infectious diseases of plants present an ongoing and increasing threat to international biosecurity, with wide-ranging implications. An important challenge in plant disease management is achieving early detection of invading pathogens, which requires effective surveillance through the implementation of appropriate monitoring programmes. However, when monitoring relies on visual inspection as a means of detection, surveillance is often hindered by a long incubation period (delay from infection to symptom onset) during which plants may be infectious but not displaying visible symptoms. 'Sentinel' plants-alternative susceptible host species that display visible symptoms of infection more rapidly-could be introduced to at-risk populations and included in monitoring programmes to act as early warning beacons for infection. However, while sentinel hosts exhibit faster disease progression and so allow pathogens to be detected earlier, this often comes at a cost: faster disease progression typically promotes earlier onward transmission. Here, we construct a computational model of pathogen transmission to explore this trade-off and investigate how including sentinel plants in monitoring programmes could facilitate earlier detection of invasive plant pathogens. Using Xylella fastidiosa infection in Olea europaea (European olive) as a current high profile case study, for which Catharanthus roseus (Madagascan periwinkle) is a candidate sentinel host, we apply a Bayesian optimisation algorithm to determine the optimal number of sentinel hosts to introduce for a given sampling effort, as well as the optimal division of limited surveillance resources between crop and sentinel plants. Our results demonstrate that including sentinel plants in monitoring programmes can reduce the expected prevalence of infection upon outbreak detection substantially, increasing the feasibility of local outbreak containment.

Real-Time Portable LAMP Assay for a Rapid Detection of Xylella fastidiosa In-Field.

Early diagnosis is part of a decision-making process which in the case of plant diseases may prevent the spread of invasive plant pathogens and assist in their eradication. Significant advantages could be obtained from moving testing technology closer to the sampling site, thereby reducing the detection time. This chapter describes a portable real-time LAMP assay for a specific detection of Xylella fastidiosa in-field. The LAMP assay, including DNA extraction, allows a complete and specific in-field analysis in just 40minutes, enabling the detection of pathogen DNA in host tissues.

Coleosporium plumeriae, causal agent of plumeria rust fungi in Yogyakarta, Indonesia, showed DNA sequence variation

Plumeria rust fungi caused by Coleosporium plumeriae is one of emerging diseases which is currently fast distributed over the world. The pathogen is also listed as an invasive plant pathogen species. This research aimed to identify Plumeria Rust Fungi from five regencies in Yogyakarta, Indonesia based on Rust2inv and LR6 Primers, which was developed from 5.8S subunit, ITS2 and 28S LSU regions to get more accurate identification of C. plumeriae. The results showed that uredospores of each specimen had variation in shape and verrucose spore walls thickness. All five specimens, which were collected from Plumeria rubra and P. alba, were identified as C. plumeriae based on homology sequences from BLAST NCBI and phylogenetic tree. Visualisation of nucleotides sequence alignment confirmed that those five specimens contain some nucleotides variations. Especially, BL specimen showed nucleotides insertions and substitutions, different from other sequences. The result performed a basic significant information for further study about genetic variations and pathogen evolution of C. plumeriae. Each specimen sequence in this study was deposited into the GenBank with accession No. OM780189- OM78019.

Domestic quarantine: An introspection and future perspectives on biosecurity interventions to contain pathogen spread in vegetatively propagated spices in India

Safeguarding biodiversity poses a major challenge that warrants preventive legislative and regulatory frameworks to ensure biosecurity, preserve intrinsic biodiversity and mitigate risks from the invasion of exotic pathogenic microbes thereby sustaining agricultural productivity and food safety. The anthropogenic activities contribute enormously towards transboundary movement of invasive alien pathogens through trade and transport of seeds/propagation materials that need to be regulated by enacting appropriate laws and policy guidelines. Black pepper, cardamom, ginger, turmeric and vanilla are the major vegetatively propagated spices cultivated in India. Since primary spread of the major pathogens in these spices are mediated through planting materials, it is imperative to formulate guidelines for flawless and meticulous implementation of quarantine measures which are otherwise not adopted. This review discusses the significance of domestic quarantine in major vegetatively propagated spices with a comprehensive background on plant biosecurity and invasive plant pathogens which could pose threat to spice cultivation in India. It further illustrates the constraints and possible strategies to annihilate the cryptically disseminated pathogens through vegetative planting materials ultimately to safeguard our self-sustaining agricultural systems.

Genic introgression from an invasive exotic fungal forest pathogen increases the establishment potential of a sibling native pathogen

Significant hybridization between the invasive North American fungal plant pathogen Heterobasidion irregulare and its Eurasian sister species H. annosum is ongoing in Italy. Whole genomes of nine natural hybrids were sequenced, assembled and compared with those of three genotypes each of the two parental species. Genetic relationships among hybrids and their level of admixture were determined. A multi-approach pipeline was used to assign introgressed genomic blocks to each of the two species. Alleles that introgressed from H. irregulare to H. annosum were associated with pathways putatively related to saprobic processes, while alleles that introgressed from the native to the invasive species were mainly linked to gene regulation. There was no overlap of allele categories introgressed in the two directions. Phenotypic experiments documented a fitness increase in H. annosum genotypes characterized by introgression of alleles from the invasive species, supporting the hypothesis that hybridization results in putatively adaptive introgression. Conversely, introgression from the native into the exotic species appeared to be driven by selection on genes favoring genome stability. Since the introgression of specific alleles from the exotic H. irregulare into the native H. annosum increased the invasiveness of the latter species, we propose that two invasions may be co-occurring: the first one by genotypes of the exotic species, and the second one by alleles belonging to the exotic species. Given that H. irregulare represents a threat to European forests, monitoring programs need to track not only exotic genotypes in native forest stands, but also exotic alleles introgressed in native genotypes.

Botanical gardens as key resources and hazards for biosecurity

Biodiversity and economic losses resulting from invasive plant pests and pathogens are increasing globally. For these impacts and threats to be managed effectively, appropriate methods of surveillance, detection and identification are required. Botanical gardens provide a unique opportunity for biosecurity as they accommodate diverse collections of exotic and native plant species. These gardens are also often located close to high-risk sites of accidental invasions such as ports and urban areas. This, coupled with routine activities such as the movement of plants and plant material, and visits by millions of people each year, place botanical gardens at risk to the arrival and establishment of pests and pathogens. Consequently, botanical gardens can pose substantial biosecurity risks to the environment, by acting as bridgeheads for pest and pathogen invasions. Here we review the role of botanical gardens in biosecurity on a global scale. The role of botanical gardens has changed over time. Initially, they were established as physic gardens (gardens with medicinal plants), and their links with academic institutions led to their crucial role in the accumulation and dissemination of botanical knowledge. During the second half of the 20th century, botanical gardens developed a strong focus on plant conservation, and in recent years there has been a growing acknowledgement of their value in biosecurity research as sentinel sites to identify pest and pathogen risks (novel pest-host associations); for early detection and eradication of pests and pathogens; and for host range studies. We identify eight specific biosecurity hazards associated with botanical gardens and note potential management interventions and the opportunities these provide for improving biosecurity. We highlight the value of botanical gardens for biosecurity and plant health research in general, and the need for strategic thinking, resources, and capacity development to make them models for best practices in plant health.

Insect herbivory facilitates the establishment of an invasive plant pathogen

Plants can be severely affected by insect herbivores and phytopathogenic fungi, but interactions between these plant antagonists are poorly understood. We analysed the impact of feeding damage by the abundant herbivore Orchestes fagi on infection rates of beech (Fagus sylvatica) leaves with Petrakia liobae, an invasive plant pathogenic fungus. The fungus was not detected in hibernating beetles, indicating that O. fagi does not serve as vector for P. liobae, at least not between growing seasons. Abundance of the fungus in beech leaves increased with feeding damage of the beetle and this relationship was stronger for sun-exposed than for shaded leaves. A laboratory experiment revealed sun-exposed leaves to have thicker cell walls and to be more resistant to pathogen infection than shaded leaves. Mechanical damage significantly increased frequency and size of necroses in the sun, but not in shade leaves. Our findings indicate that feeding damage of adult beetles provides entry ports for fungal colonization by removal of physical barriers and thus promotes infection success by pathogenic fungi. Feeding activity by larvae probably provides additional nutrient sources or eases access to substrates for the necrotrophic fungus. Our study exemplifies that invasive pathogens may benefit from herbivore activity, which may challenge forest health in light of climate change.

A study of Phytophthora spp. in declining highbush blueberry in Germany reveals that P. cinnamomi can thrive under Central European outdoor conditions

Phytophthora cinnamomi and P. cactorum were detected in soil samples from a Vaccinium corymbosum stand in southern Germany. Both species were virulent in an underbark inoculation assay and have not been reported from highbush blueberry in Germany before. While P. cactorum is a widely distributed species in nurseries and (semi)natural habitats like forests, field reports of P. cinnamomi in Germany are rare due to its sensitivity to frost. Its occurrence in an outdoor blueberry stand indicates its potential to survive Central European winter periods that tend to be increasingly mild. Phytophthora cinnamomi was also found in the substrate of young V. corymbosum nursery plants, suggesting a high degree of contamination in commercial blueberry production and demonstrating the risk of spreading exotic invasive plant pathogens via planting of infested nursery stock.

Catalogue of pests and pathogens of trees on the island of Ireland

The health and sustainability of trees are increasingly under threat from biotic and abiotic sources, including rising incidences of non-native invasive plant pests and pathogens. The island of Ireland (Ireland and Northern Ireland) is generally understood to have a high plant health status, due to its island status and because of the national and international regulations aimed at protecting plant health. To establish a baseline of the current pest and pathogen threats to tree health for the island of Ireland, the literature and unpublished sources were reviewed to produce a dataset of pests and pathogens of trees on the island of Ireland. Thedataset contains 396 records—the majority of pests and pathogens being arthropods and fungi—and indicates potentially more than 44 non-native pest and pathogen introductions. The reliability of many (378) of the records was judged to be high, therefore the dataset provides a robust assessment of the state of pests and pathogens of trees recorded on the island of Ireland. We analyse this dataset and review the history of plant pest and pathogen invasions; in doing so, we discuss (i) notable native and non-native pests and pathogens of trees, (ii) interceptions at borders and (iii) pests, pathogens and climate change. The dataset establishes an important baseline for the knowledge of plant pests and pathogens on the island of Ireland, and will be a valuable resource for future plant health research and policy making.

Austropuccinia psidii, causing myrtle rust, has a gigabase-sized genome shaped by transposable elements.

Austropuccinia psidii, originating in South America, is a globally invasive fungal plant pathogen that causes rust disease on Myrtaceae. Several biotypes are recognized, with the most widely distributed pandemic biotype spreading throughout the Asia-Pacific and Oceania regions over the last decade. Austropuccinia psidii has a broad host range with more than 480 myrtaceous species. Since first detected in Australia in 2010, the pathogen has caused the near extinction of at least three species and negatively affected commercial production of several Myrtaceae. To enable molecular and evolutionary studies into A. psidii pathogenicity, we assembled a highly contiguous genome for the pandemic biotype. With an estimated haploid genome size of just over 1 Gb (gigabases), it is the largest assembled fungal genome to date. The genome has undergone massive expansion via distinct transposable element (TE) bursts. Over 90% of the genome is covered by TEs predominantly belonging to the Gypsy superfamily. These TE bursts have likely been followed by deamination events of methylated cytosines to silence the repetitive elements. This in turn led to the depletion of CpG sites in TEs and a very low overall GC content of 33.8%. Compared to other Pucciniales, the intergenic distances are increased by an order of magnitude indicating a general insertion of TEs between genes. Overall, we show how TEs shaped the genome evolution of A. psidii and provide a greatly needed resource for strategic approaches to combat disease spread.

Optimising risk-based surveillance for early detection of invasive plant pathogens.

Emerging infectious diseases (EIDs) of plants continue to devastate ecosystems and livelihoods worldwide. Effective management requires surveillance to detect epidemics at an early stage. However, despite the increasing use of risk-based surveillance programs in plant health, it remains unclear how best to target surveillance resources to achieve this. We combine a spatially explicit model of pathogen entry and spread with a statistical model of detection and use a stochastic optimisation routine to identify which arrangement of surveillance sites maximises the probability of detecting an invading epidemic. Our approach reveals that it is not always optimal to target the highest-risk sites and that the optimal strategy differs depending on not only patterns of pathogen entry and spread but also the choice of detection method. That is, we find that spatial correlation in risk can make it suboptimal to focus solely on the highest-risk sites, meaning that it is best to avoid 'putting all your eggs in one basket'. However, this depends on an interplay with other factors, such as the sensitivity of available detection methods. Using the economically important arboreal disease huanglongbing (HLB), we demonstrate how our approach leads to a significant performance gain and cost saving in comparison with conventional methods to targeted surveillance.

Using spatial models to identify refugia and guide restoration in response to an invasive plant pathogen

Abstract The global spread of invasive plant pathogens is increasing, putting natural forests and ecosystem services under threat. Spatial data can quantify range non‐overlap between invasive pathogens and their hosts to identify existing and potentially restorable refugia to enable ‘escape’ from the pathogen. In 2017, myrtle rust Austropuccinia psidii was detected in New Zealand. New Zealand has 27 native woody and liana species in the plant family susceptible to the disease (Myrtaceae), many of which are ecosystem dominants and economically important. Spatial methods were used to compare the current New Zealand distribution of myrtle rust with the modelled distributions of its potential native hosts. To guide management and set priorities for conservation of at‐risk species, areas of potential refugia where a Myrtaceae species is predicted to occur outside the pathogen range were identified under two myrtle rust distribution scenarios. Myrtle rust will thrive in New Zealand's warmer regions. Many native Myrtaceae are distributed within this area, but several species occur extensively outside the core range of the disease. Species distributed in cooler southern regions will be best placed to persist in refugia. Myrtaceae species with specific habitat requirements and narrow geographical ranges in warmer (northern) areas are likely to require ex situ or active in situ management. Even widely distributed species will benefit from the restoration of suitable habitat that supports multiple species outside the myrtle rust range. Synthesis and applications. Spatial data can be used to identify refugia and restoration opportunities, and thus inform landscape‐level management responses to invasive pathogens. This approach can guide decisions over where to implement in situ (e.g. fungicide spraying) versus ex situ (e.g. seed banking, botanic gardens) management efforts.