Botanic Gardens Trust, Sydney, Australia

Plant Pathology and Mycology research 2010-2011

Zoe-Joy Newby - PhD Candidate
Dr Edward Liew - Manager Plant Pathology

On-going work in the Plant Pathology and Mycology research program includes documenting and describing foliar diseases of members of the Proteaceae and Myrtaceae, describing new species of the fungal genus Fusarium, understanding the biogeography and evolution of soil inhabiting and endophytic species of Fusarium, studying movement and distribution of economically significant Fusarium pathogens and investigating disease management strategies for a range of diseases incited by the water mould Phytophthora. Research on Phytophthora includes management of Phytophthora Dieback throughout the Greater Blue Mountains World Heritage Area (GBMWHA), including Phytophthora Root Rot at the Wollemi Pine site.

Research Highlight

Phytophthora cinnamomi has a worldwide distribution and has been associated with large scale dieback of native ecosystems in most states of Australia. Plant Pathology PhD candidate Zoe-Joy Newby has been investigating the distribution and impact of P. cinnamomi across the GBMWHA. Inscribed on the world heritage list in 2000, the one million hectares of interconnected parks and reserves is recognised as a major centre of biological diversity and processes. Using traditional field-based methods combined with novel geographical information systems and remote sensing, Zoe-Joy is exploring the impact of disease and defining management recommendations for the region.

A preliminary risk assessment was developed using GIS and defined geographically the potential level of Phytophthora infection across the WHA. Based on the model, the Blue Mountains National Park was most at risk given its idyllic temperatures and rainfall patterns combined with an already high presence of the pathogen. Conversely the northern-most regions of the Wollemi NP appeared to be less preferential to P. cinnamomi due to warmer temperatures occurring in that area.

This risk assessment was subsequently stratified and used to design a randomised soil sampling survey. While the sampling is still in progress, over 1300 samples have been collected and tested to date, with additional samples being provided by generous members of the public and the NPWS. From these samples 144 isolates of Phytophthora have been obtained, which include 121 P. cinnamomi, 71% of which obtained from the Blue Mountains NP. Information from the soil survey will now be used to model the distribution of P. cinnamomi and predict the environmental inputs most significant in the establishment of Phytophthora. The results are also being used to train GIS software to recognise dieback locations from satellite imagery, thereby allowing disease assessments of remote areas of the park that cannot be reached on foot. Practical implications from the results highlight the urgent need, not only for disease management, but conservation considerations to an area that is highly prone to the spread of Phytophthora, given the concentration of recreation activities.

Zoe-Joy is also working closely with NPWS and community groups to spread awareness of Phytophthora Dieback in native ecosystems, and facilitating disease management from individuals right through to government and industry agencies. 

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Phytophthora Dieback location identified at Glenbrook in the lower Blue Mountains.

Banksia-spinulosa-infected-with-Phytopthora
B. spinulosa showing symptoms of Phytophthora Dieback.

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Zoe-Joy collecting soil from a diseased Petrophile sp. in the Newens State Forest

Viv-Young-inspecting-lupin-baits
Garden volunteer, Vivien Young, inspects Phytophthora baits for the presence of sporangia (spore sacs).

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Microscopic view of sporangia produced on plant roots. Sporangia contain infective zoospores that are released into soil water and swim to a new host.

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Current soil sampling results for the GBMWHA 

All photos: Zoe-Joy Newby