Myrtle rust, impacts on Myrtaceous diversity in Australia Geoff Pegg DAF Queensland

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1 Myrtle rust, impacts on Myrtaceous diversity in Australia Geoff Pegg DAF Queensland Fiona Giblin - USC Angus Carnegie NSW DPI Suzy Perry DAF Queensland

2 What is myrtle rust & why is it so significant to Australia? Myrtle rust Rust fungus Puccinia psidii = guava/eucalypt rust multiple strains Myrtaceae in Australia >2250 species from 88 genera within Australia Includes some iconic species Dominate many fragile and essential ecosystems Coastal wetlands Wet & dry sclerophyll forests Important socially & commercially Indigenous Bush foods Oil and food & fibre production Tourism World Heritage areas

3 Spread in Australia Melville Island 2015 Bamaga 2015 North Queensland April 2012 Central Queensland Jan 2012 Northern Territory Queensland Brisbane, Queensland Dec 2010 Western Australia South Australia New South Wales First detected April 2010; Gosford, NSW Victoria Dec 2011 Tasmania 2015 Victoria Tasmania

4 Distribution Myrtle rust has now been identified from a range of native forest ecosystems Coastal heath & wetlands Sand islands Littoral, montane, subtropical and tropical rainforests

5 Host range 347 species from 57 different genera Natural infection = 232 Inoculated studies only = species rated as highly or extremely susceptible Based only Qld field assessments Giblin FR & Carnegie AJ (2014) Puccinia psidii (Myrtle rust) - Australian host list. Version current at 23 Oct

6 Impact on threatened Myrtaceae Queensland Conservation Status Endangered Backhousia oligantha Gossia fragrantissima Gossia gonoclada Lenwebbia sp. Blackall Range Rhodamnia angustifolia Vulnerable Eucalyptus argophloia Homoranthus papillatus Leptospermum luehmannii Mitrantia bilocularis Ristantia waterhousei Sphaerantia discolor Syzygium moorei Xanthostemon oppositifolius Myrtle rust susceptibility rating Highly/Extremely susceptible Moderately susceptible Relatively tolerant Unknown 23 species listed in Queensland as being threatened before myrtle rust 11 of these species have been identified as being highly/extremely susceptible to myrtle rust Near Threatened Eucalyptus curtisii Gossia inophloia (Austromyrtus) Lenwebbia prominens Melaleuca formosa (Callistemon) Rhodamnia glabrescens Rhodamnia pauciovulata Stockwellia quadrifida Syzygium aqueum Syzygium macilwraithianum Waterhousea mulgraveana Gossia gonoclada

7 Threatened species - Lenwebbia sp. Blackall Range Assessed for impact across its native range Significant impact All life stages Seedlings Saplings Mature trees Infection on flowers A single tree identified with no disease Species recommended to be listed as Critically Endangered

8 Threatened species - Rhodamnia angustifolia 12 trees remain in the natural population Myrtle rust impact Significant foliage loss and rapid dieback No flower/fruit production recorded since arrival of rust March 2011 June 2012

9 Impact on widespread species Rhodomyrtus psidioides Native guava Conservation status Least Concern Fast growing Important successional role in rainforest regeneration Myrtle rust impact Most populations consist entirely of dead or dying trees Impacting on all life stages Regenerating seedlings & root suckers infected &/or killed Flowers/fruit infected Carnegie et al. Submitted 2015

10 Peter Entwistle

11 Rhodomyrtus psidioides seedlings/coppice

12 Impact on widespread species Rhodamnia rubescens Malletwood Conservation status Least Concern Common rainforest/ rainforest margin species Fruit eaten by range of bird species Myrtle rust impact Variability in impact levels?? Resistance Flower & fruit death Seedling deaths recorded Carnegie et al. unpublished

13 Unsprayed Sprayed Significant increase in foliage production on fungicide-sprayed trees after 6 months

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17 Fire & Rust- Impact on ecosystem regeneration Wildfires are common in Australia Plant species are well adapted to fire Coppice regrowth Seed release and germination What will the impact of myrtle rust be on regeneration after fire? Study site in coastal heath (Wallum) ecosystem burnt in December sites wet and dry heath 10 species from 4 different genera of Myrtaceae

18 Dry heath species susceptibility Species Rust susceptibility Trees with dieback (%) Dieback severity (branch death per tree %) Flower/fruit affected Melaleuca nodosa High Extreme Y Austromyrtus dulcis Resistant Moderate Y high % Leptospermum polygalifolium Resistant - Moderate 0 0? Leptospermum whitei Resistant - Low 0 0?

19 Melaleuca nodosa Infection on young shoots Dieback and stem swellings Severe dieback following repeated infection

20 Wet heath species susceptibility Species Rust susceptibility Trees with dieback (%) Dieback severity (branch death per tree %) Flower/fruit affected Leptospermum trinervium Moderate - Extreme ? Leptospermum liversidgeii Moderate - Extreme Baeckea linifolia Resistant Moderate Melaleuca quinquenervia Resistant - Extreme ? Y Y Melaleuca rigidus Low - Moderate N Leptospermum whitei Lophostemon suaveolens Resistant - Low 30 20? Resistant Low 0 0 N

21 Leptospermum liversidgeii

22 Leptospermum trinervium

23 Keystone species - Melaleuca quinquenervia Ecologically significant species Maintenance of waterways Habitat and food source Impact of rust on regeneration following disturbance Establishment & growth of seedlings/saplings Flower/seed production Coppice regeneration Interaction with insects Resistance/susceptibility

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25 Melaleuca quinquenervia coppice regeneration 30% of trees rated as resistant Rating 1 40% of trees rated as highly susceptible Rating 4 & 5 Rating 1 - Resistant Rating 4&5 Dead

26 Incidence of insect attack (%) Incidence of rust infection (%) Nov-14 Dec-14 Feb-15 Apr-15 May-15 Jul Rust/insect interaction study Insect Incidence Rust incidence 0 Nov-14 Dec-14 Feb-15 Apr-15 May-15 Jul-15 Control Fungicide Fungicide & Insecticide Insecticide Control Fungicide Fungicide & Insecticide Insecticide Rust and insect exclusion trial examining impact on coppice regeneration Treated and assessed monthly

27 Interaction Insecticide + fungicide Untreated control

28 Insecticide May 2015 July 2015

29 Summary Impact on threatened and widespread species Already seeing changes in species composition How do we conserve species in rapid decline? What will the long-term effects be? Wildfires Can we reduce impact through better fire management? Keystone species Change in genetic diversity? Change in ecosystem function? Regeneration programs using resistant material?

30 Thank you CRC Plant Biosecurity Peter Entwistle, Gordon Guymer, David Lee, John Huth, Bob Makinson, Jali Land Council For more information, please