Pacific Pests, Pathogens, Weeds & Pesticides - Online edition

Pacific Pests, Pathogens, Weeds & Pesticides

Citrus butt & root rot (004)

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Photo 1. Ganoderma sp. growing from the base of an orange tree, which is still alive. Note the dark upper surface with the distinctive white margin.

Photo 2. Another Ganoderma species. The young backets can be seen on the left of the trunk. In this case the tree is dead.

Photo 3. Underside of Photo 1, showing the light grey colour of this active spore producing-bracket.

Summary

  • Worldwide distribution. The fungi that cause these diseases (commonly, Ganoderma and Trametes) have a very wide host range, including many forest, fruit and plantation trees, including palms. Important diseases.
  • The fungi cause white rots in roots and trunks, causing slow dieback and death. The brackets that develop remain for many years, producing millions of spores.
  • Spread is either root-to-root or spores infect through wounds. Spores travel long distances on the wind.
  • Cultural control: make regular checks for brackets and, if found, dig out infected trees, with the main roots, and burn; seek the source of infection, e.g., old stump of forest tree; plant ground legumes to hasten decay of stumps; do not damage healthy trees: stop people cutting the bark with bush knives!
  • Chemical control: none recommended.

Common Name

Butt and root rot

Scientific Name

Ganoderma and Trametes. There are many species of both, and not all are plant pathogens, especially those belonging to Trametes. Also, see Casuarina butt rot caused by Ganoderma applanatum (Fact Sheet no. 195).

Photo 4. Tremetes on a dead citrus trunk showing stacks of brackets, one on top of the other.

AUTHORS Helen Tsatsia & Grahame Jackson
Information from Futch SH, et al. (undated) Ganoderma wood-rotting fungi on citrus stumps. University of Florida Extension Service. (https://edis.ifas.ufl.edu/hs269); Dewdney M (2012) Ganoderma root rot. University of Florida-IFAs's Citrus Research and Education Center in Lake Alfred. (https://crec.ifas.ufl.edu/extension/trade_journals/2012/2012_December_ganoderma.pdf); and from Downer AJ, Perry EJ (2019) Wood decay fungi in landscape trees. University of California Statewide IPM Program. Agriculture and Natural Resources, University of California. (http://ipm.ucanr.edu/PMG/PESTNOTES/pn74109.html).

Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.

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