Brown root rot

Brown root rot disease is caused by the fungus Phellinus noxius. The fungus attacks tree roots causing decay. This cuts off water and nutrient supply to the crown, causing tree death. Occurring naturally in rainforests, the disease has become a problem in forest plantations, fruit orchards and urban environments.

Scientific name

Phellinus noxius

Description

  • A 'stocking' forms on roots and tree trunk with a white margin when actively growing, turning cinnamon-brown with age.
  • Not all infected trees display a stocking.
  • Fruiting bodies only develop after extended periods of rain.
  • Resupinate (upside-down) form is flat and grows flush with the bark.
  • Bracket fruiting bodies are leathery or woody and hard.

Distribution

East coast of Queensland to northern New South Wales including:

  • rainforests
  • commercial plantation forests
  • fruit orchards
  • amenity plantings in urban areas.

Hosts

More than 200 species of native and introduced trees and shrubs including:

  • palm
  • fig
  • poinciana
  • leopard tree
  • avocado
  • hoop pine.

Damage

  • In young trees, wilting is often followed by rapid death.
  • In older trees, leaves gradually turn chlorotic (pale yellow and white), the crown thins and the tree eventually dies.

Biology

  • Spreads by root-to-root contact, and potentially with air-borne basidiospores produced by fruiting bodies.
  • Stumps from infected trees are sources of infection.
  • Can remain in the soil for 60 years.

Monitoring and action

  • Remove the entire infected tree and as many roots as possible, and:
    • compost for at least 16 weeks, so the piles reach 75ºC, and turn over regularly
    • sieve material greater than 18mm out of the final compost before using.
  • Install root barriers around the infected site to reduce spreading.
  • Don't use infected trees for mulch without composting as described above.
  • New plantings in infested sites may rapidly die if you do not remove the source of the infection.

Resources and research

Contact

General enquiries 13 25 23