1. Phellinus noxius: Brown root rot of
avocado
Elizabeth Dann, Luke Smith, Ken
Pegg
Fruit Pathology Team, Indooroopilly
Michelle Grose, Geoff Pegg
Forestry Pathology, Indooroopilly

2. Queensland Primary Industries and Fisheries
Phellinus noxius
• Widespread in tropical and subtropical regions of
southeast Asia, Africa, Oceania (including Australia),
Japan and Central America and the Caribbean
• Wide host range affecting 200 tree and plant species
including avocado, mango, litchi, hoop pine and other
forestry species as well as amenity trees in parks and
gardens
• Diverse environments from rainforests and sand
dunes to dry inland regions
• Important decay and recycling agent of dead wood in
undisturbed environments
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

3. Queensland Primary Industries and Fisheries
History in Australia
• Tentatively identified in 1952 from fruiting bodies on
hoop pine
• Symptoms of progressive avocado tree death along
rows observed on the Atherton Tablelands in Qld in
2001
• First positive identification of P. noxius causing
avocado tree death in Maleny in Qld in 2002
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

4. Queensland Primary Industries and Fisheries
Symptoms
• Rapid tree decline and death
• Leaves and fruit will often be left hanging on
tree
• Infection stocking advancing up trunk
• Leaves, sticks and soil stuck to trunk of tree
by infection stocking
• Mycelial felt between bark and wood
• Dead wood behind infection stocking
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

5. Queensland Primary Industries and Fisheries
Tree Decline & Death
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

6. Queensland Primary Industries and Fisheries
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

7. Queensland Primary Industries and Fisheries
Infection “stocking”
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

8. Queensland Primary Industries and Fisheries
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

9. Queensland Primary Industries and Fisheries
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

10. Queensland Primary Industries and Fisheries
Mycelial felt
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

11. Queensland Primary Industries and Fisheries
Dead wood
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

12. Queensland Primary Industries and Fisheries
Infection Process
• Typically by root contact with infested woody
material in soil
• Spreads between trees where infected roots
of one tree contact healthy roots of
neighboring tree – root to root contact
• May also be through airborne basidiospores
where fruiting bodies present (though
uncommon in avocados)
• Persists in woody debris in the soil for many
years © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

13. Queensland Primary Industries and Fisheries
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

14. Queensland Primary Industries and Fisheries
Scoping Study
• Approximately 30 avocado orchards in
Atherton Tablelands & Childers/Bundaberg
productions regions, Sunshine Coast and
northern New South Wales visited from 2007
- 2009
• P. noxius confirmed on 17 Atherton, 5
Childers/Bundaberg, 1 Sunshine Coast and 2
northern NSW orchards
• Likely to be present on more orchards
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

15. Queensland Primary Industries and Fisheries
Scoping Study
• Severity ranged from minor (a few trees
affected) to severe (80% of trees in a block)
• Extent of stocking development not indicative
of severity of disease affecting a tree
– Some dead trees had limited stocking
development
– Extensive stocking development on trees
that had not succumbed
• Replanting typically failed
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

16. Queensland Primary Industries and Fisheries
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

17. Queensland Primary Industries and Fisheries
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

18. Queensland Primary Industries and Fisheries
Control
• Removal of infected trees
• Installation of root barriers to prevent spread
• No current chemical control measures
registered
• Promising control options in literature that
may be effective in avocado.
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

19. Queensland Primary Industries and Fisheries
Root Barriers
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

20. Queensland Primary Industries and Fisheries
Acknowledgements
• HAL
• Avocados Australia
• Eddie Dunn, Crop Tech, Bundaberg
• Matthew Weinert, QPIF, Mareeba
• David Peasley, Peasley Horticultural Services
• All the growers visited during the scoping study
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009