Nari Williams


  • Phone: +64 7 343 5535
  • Email: Show email
  • Team: Forest Protection
  • Role: Forest Pathologist


Nari specialises in pathology, management and systems biology of Phytophthora diseases. Nari has 18 years’ experience working with Phytophthora species having completed her PhD investigating DNA based diagnostic methods for Phytophthora detection at The Centre for Phytophthora Science and Management based at Murdoch University in Western Australia. Nari’s current research focusses on Phytophthora pathogens of importance to New Zealand’s natural and production plant systems including the red needle cast of radiata pine (Phytophthora pluvialis) and kauri dieback (Phytophthora agathadicida). Nari leads the Healthy trees, healthy future: enabling technologies to combat Phytophthora diseases programme. This is a collaboration between Scion, Plant and Food Research, Landcare Research, Massey University and the University of Auckland.


  • PhD (Biotechnology – Plant Pathology), Murdoch University, Australia
  • B.Ag.Sc (Hons) (Integrated Pest Management), The University of Adelaide, Australia -2002

Research capabilities

  • Plant pathology
  • Phytophthora diseases
  • Epidemiology and management of Phytophthora diseases
  • Systems biology

Selected papers

Scott, P., Bader, MKF., Burgess, T., Hardy, G., Williams, N., (2019) Global biogeography and invasion risk of the plant pathogen genus Phytophthora (2019) Environmental Science & Policy 101, 175-182.

Della Rocca, G., Danti, R., Williams, N., Eyre, C., Garbelotto, M., (2019) Molecular analyses indicate that both native and exotic pathogen populations serve as sources of novel outbreaks of Cypress Canker Disease Biological Invasions 21 (9), 2919-2932.

Can Copper Be Used to Treat Foliar Phytophthora Infections in Pinus radiata? C Rolando, C Somchit, MKF Bader, S Fraser, N Williams. Plant disease, PDIS-07-18-1247-RE.

Gómez-Gallego, M., Leboldus, J.,Bader, M.K-F., Hansen, E.,Donaldson, L., Williams, N.M. (2019). “Contrasting the pathogen loads in co-existing populations of Phytophthora pluvialis and Nothophaeocryptopus gaeumannii in Douglas-fir plantations in New Zealand and the US Pacific Northwest.” Phytopathology. DOI:

LeBoldus, JM, Keriö, SE, Daniels, HA, Gómez-Gallego, M, Tabima-Restrepo, J, Lenz, RR, Søndreli, KL, Grünwald, NJ, Williams, NM and McDougal, RL, (2019). From genomes to forest management – tackling invasive Phytophthora species in the era of genomics. Canadian Journal of Plant Pathology.

Scott P, Taylor P, Williams N (2019). Contrasting the infection and survival of Phytophthora pluvialis and Phytophthora cinnamomi in Pinus radiata roots. Australasian Plant Pathology. DOI 10.1007/s13313-019-0619-7.

Lewis K, Black A, Waipara N, Scott P, Williams N, O’Callaghan M (2019). Land use changes influence the sporulation and survival of Phytophthora agathidicida, a lethal pathogen of New Zealand kauri (Agathis australis). Forest Pathology: e12502. DOI 10.1111/efp.12502.

Scott PM, Taylor P, Gardner J, Puertolas, Panda P, Addison S, Hood I, Burgess T, Horner I, Williams N, McDougal R (2019). Phytophthora aleatoria sp. nov., a root and collar pathogen of Pinus radiata from nurseries and plantations. Australasian Plant Pathology.

Gómez-Gallego M, Gommers, R, Bader, MK, Williams N (2019). Modelling the key drivers of an aerial Phytophthora foliar disease epidemic, from the needles to the whole plant. Accepted In Press. PLoS One. 14(5):e0216161.

Studholme, D., Panda, P, Von Stowasser, E Sanfuentes, González, M, Hill, R, Sambles, C, Grant, M, Williams, NM, McDougal, RL. (2018) "Genome sequencing of oomycete isolates from Chile supports the New Zealand origin of Phytophthora kernoviae and makes available the first Nothophytophthora sp. genome." Molecular Plant Pathology. 

Hunter, S, McDougal, R, Clearwater, M, Williams, N, Scott, P (2018) Development of a high throughput optical density assay to determine fungicide sensitivity of oomycetes. Journal of Microbiological Methods 154 33-39.

Bradshaw R, Scott PM, Williams NM, Herewini E (2018). In vitro assays of Phytophthora agathidicida on kauri leaves suggest variability in pathogen virulence and host response. New Zealand Plant Protection, 71.

Graham, N. J., Suontama, M, Pleasants, T., Li, Y. Bader, MK-F, Klápště, J., Dungey, HS., Williams, NM. (2018). "Assessing the genetic variation of tolerance to red needle cast in a Pinus radiata breeding population." Tree Genetics & Genomes 14(4): 55.

Wake, G.; Williams, N.; Pleasants, T. (2018). A dynamical systems model for poly-cyclic foliar forest pathogens. ANZIAM J. 59 (EMAC2017) pp.C1–C14, 2018. doi:10.21914/anziamj.v59i0.anziam.

Donaldson, L.; Williams, N. (2018). Imaging and Spectroscopy of Natural Fluorophores in Pine Needles. Plants 2018, 7, 10. 

Brar, S., Tabima, J. F., McDougal, R. L., Dupont, P. Y., Feau, N., Hamelin, R. C., Panda, P., LeBoldus, J. M., Grünwald, N. J., Hansen, E. M., Bradshaw, R. E., & Williams, N. M. (2017). Genetic diversity of Phytophthora pluvialis, a pathogen of conifers, in New Zealand and the west coast of the United States of America. Plant Pathology.  doi:10.1111/ppa.12812

Dickie, I. A., Bufford, J. L., Cobb, R. C., Desprez‐Loustau, M. L., Grelet, G., Hulme, P. E., . Pringle, A., Thrall, P.H., Tourtellot, S.G., Waller, L., and Williams, N.M., (2017). The emerging science of linked plant–fungal invasions. New Phytologist, 215(4), 1314-1332.

Gómez-Gallego, M., Bader, M. K., Scott, P., Leuzinger, S., & Williams, N. (2017). Phytophthora pluvialis studies on Douglas fir require Swiss needle cast suppression. Plant Disease(ja).

Carol A Rolando, Margaret A Dick, Judy Gardner, Martin K-F Bader, Nari M Williams (2017) Chemical control of two Phytophthora species infecting the canopy of Monterey pine (Pinus radiata). Forest Pathology. In Press

Scott, P., Bader, M. K.-F., & Williams, N. M. (2016). Foliar phosphite application has minor phytotoxic impacts across a diverse range of conifers and woody angiosperms. Physiologia Plantarum, n/a-n/a. doi:10.1111/ppl.12442

Studholme, D., McDougal, R., Sambles, C., Hansen, E., Hardy, G., Grant, M., Williams, N. (2016). Genome sequences of six Phytophthora species associated with forests in New Zealand. Genomics Data, 7, 54-56.

Hansen, E., Reeser, P., Sutton, W., Gardner, J., & N., W. (2015). First report of Phytophthora pluvialis causing needle loss and shoot dieback on Douglas-fir in Oregon USA and New Zealand. Plant Disease Research, In Press.

Dungey, H. S., Williams, N. M., Low, C. B., & Stovold, G. T. (2014). First evidence of genetic-based tolerance to red needle cast caused by Phytophthora pluvialis in radiata pine. New Zealand Journal of Forestry Science, 44(1), 31.

Ganley, R. J., Williams, N. M., Rolando, C. A., Hood, I. A., Dungey, H. S., Beets, P. N., & Bulman, L. S. (2014). Management of red needle cast, caused by Phytophthora pluvialis, a new disease of radiata pine in New Zealand. New Zealand Plant Protection, 67, 48-53.

Pawson, S., Williams, N., Gear, I., & Armstrong, J. (2014). Reducing biosecurity business risks for logs and timber. New Zealand Journal of Forestry, 59(2), 22-28.

Scott, P. M., & Williams, N. M. (2014). Phytophthora diseases in New Zealand forests. New Zealand Journal of Forestry, 59(2), 14-21.

Dick, M. A., Williams, N. M., Bader, M., Gardner, J., & Bulman, L. S. (2014). Pathogenicity of Phytophthora pluvialis to Pinus radiata and its relation with red needle cast disease in New Zealand. New Zealand Journal of Forestry Science, 44(6), 1-12.

Hood, I. A., Williams, N. M., Dick, M. A., Arhipova, N., Kimberley, M., & Gardner, J. (2014). Decline in vitality of propagules of Phytophthora pluvialis and Phytophthora kernoviae and their inability to contaminate or colonise bark and sapwood in Pinus radiata export log simulation studies. New Zealand Journal of Forestry Science, 44(7), 1-13.

Rolando, C., Gaskin, R., Horgan, D., Williams, N., & Bader, M. K. (2014). The use of adjuvants to improve uptake of phosphorous acid applied to Pinus radiata needles for control of foliar Phytophthora diseases. New Zealand Journal of Forestry Science, 44(1), 1-7.

Li, A. Y., Crone, M., Adams, P. J., Fenwick, S. G., Hardy, G. E. S. J., & Williams, N. (2014). The Microscopic Examination of Phytophthora cinnamomi in Plant Tissues Using Fluorescent In Situ Hybridization. Journal of Phytopathology, n/a-n/a. doi: 10.1111/jph.12257

Li, A., Williams, N., Fenwick, S., Hardy, G. S. J., & Adams, P. (2014). Potential for dissemination of Phytophthora cinnamomi by feral pigs via ingestion of infected plant material. Biological Invasions, 16(4), 765-774. doi: 10.1007/s10530-013-0535-7

O'Brien, P. A., Williams, N., & Hardy, G. E. (2009). Detecting phytophthora. Critical Reviews in Microbiology, 35(3), 169-181.

Cai, Y. F., Barber, P., Dell, B., O'Brien, P., Williams, N., Bowen, B., & Hardy, G. (2010). Soil bacterial functional diversity is associated with the decline of Eucalyptus gomphocephala. Forest Ecology and Management, 260(6), 1047-1057.

King, M., Reeve, W., Van Der Hoek, M. B., Williams, N., McComb, J., O'Brien, P. A., & Hardy, G. E. S. J. (2010). Defining the phosphite-regulated transcriptome of the plant pathogen Phytophthora cinnamomi. Molecular Genetics and Genomics, 284(6), 425-435. doi: 10.1007/s00438-010-0579-7

Facelli, E., Taylor, C., Williams, N. M., Emmett, R. W., Sedgley, M., Joyce, C. K., & Scott, E. S. (2009). Location of Xanthomonas translucens in pistachio trees. Australasian Plant Pathology, 38(6), 584-593. doi: Doi 10.1071/Ap09044

Williams, N., Hardy, G. E. S. J., & O'Brien, P. A. (2009). Analysis of the distribution of Phytophthora cinnamomi in soil at a disease site in Western Australia using nested PCR. Forest Pathology, 39(2), 95-109.

Anderson, N., Szemes, M., O'Brien, P., De Weerdt, M., Schoen, C., Boender, P., & Bonants, P. (2006). Use of hybridization melting kinetics for detecting Phytophthora species using three-dimensional microarrays: demonstration of a novel concept for the differentiation of detection targets. Mycological Research, 110(6), 664-671.

Hardy, G. E. S. J., Vear, K., O'Gara, E., & Williams, N. M. (2004). Detection, diagnosis and mapping of native areas infested by Phytophthora species in Western Australia. Brazilian Phytopathology, 32 (Supplement), S45-S46.