Phellinus noxius, also known as brown root rot, is a fungus that causes rapid tree decline and death in avocado trees. It has a wide host range and is widespread in tropical and subtropical regions. In Australia, it was first identified infecting avocado trees in Queensland in the early 2000s. Symptoms include leaves and fruit remaining on dead trees, an infection stocking advancing up the trunk, and dead wood behind the stocking. The fungus spreads between trees through root contact in soil and can persist for many years in woody debris. A scoping study found the fungus infecting many avocado orchards across Queensland and New South Wales.
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Luke Smith
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
息 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
息 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
息 The State of Queensland, Department of Employment, Economic Development and Innovation, 2009
5. Queensland Primary Industries and Fisheries
Tree Decline & Death
息 The State of Queensland, Department of Employment, Economic Development and Innovation, 2009
6. Queensland Primary Industries and Fisheries
息 The State of Queensland, Department of Employment, Economic Development and Innovation, 2009
7. Queensland Primary Industries and Fisheries
Infection stocking
息 The State of Queensland, Department of Employment, Economic Development and Innovation, 2009
8. Queensland Primary Industries and Fisheries
息 The State of Queensland, Department of Employment, Economic Development and Innovation, 2009
9. Queensland Primary Industries and Fisheries
息 The State of Queensland, Department of Employment, Economic Development and Innovation, 2009
10. Queensland Primary Industries and Fisheries
Mycelial felt
息 The State of Queensland, Department of Employment, Economic Development and Innovation, 2009
11. Queensland Primary Industries and Fisheries
Dead wood
息 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 息 The State of Queensland, Department of Employment, Economic Development and Innovation, 2009
13. Queensland Primary Industries and Fisheries
息 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
息 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
息 The State of Queensland, Department of Employment, Economic Development and Innovation, 2009
16. Queensland Primary Industries and Fisheries
息 The State of Queensland, Department of Employment, Economic Development and Innovation, 2009
17. Queensland Primary Industries and Fisheries
息 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.
息 The State of Queensland, Department of Employment, Economic Development and Innovation, 2009
19. Queensland Primary Industries and Fisheries
Root Barriers
息 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
息 The State of Queensland, Department of Employment, Economic Development and Innovation, 2009