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Pest Library
Recognition: |
Wood affected by brown rot acquires a brownish stain,
and shrinks abnormally during drying, resulting in a cracked, cube-like
appearance. The cracks run perpendicular to the natural woodgrain.
When this cube shaped wood is dry, it crushes easily into powder.
Brown rot produces fruiting bodies which look like crusts, shelves,
or mushrooms, with a tough, leathery, corky or woody texture when
mature. |
Geographic Range: |
Brown rot occurs throughout most of the United States where there
is abundant moisture. |
Comparison with other groups: |
Some sap-staining fungi do cause brown or black stains, but do
not result in abnormal shrinkage of the wood into brittle cubes that
crumble when crushed. Surface-staining fungi which also result in
brown or black stains give the wood surface a powdery or fuzzy appearance,
but these types do not produce shrinkage or cubes either. |
Biology: |
Brown rot is spread by spores. Brown rot hyphae attack the wood's
sugars and starches, as well as the cellulose of the cell walls. This
can reduce the strength of the wood, and cause it to absorb more moisture.
Some brown rot fungi can withstand high heat and dryness. Some species
can remain dormant for long periods, and then revive when moisture
is present. |
Damage: |
Brown rot fungi mostly attack softwoods, such as pine, spruce,
and fir, with a wood moisture content of 28-32% or more. |
Detection: |
- Affected wood becomes brownish. While drying the wood tends
to crack perpendicular to the grain, resulting in cube-like structures
which are easily crushed into powder when dry.
- A thorough inspection is needed in order to identify the source
of moisture, and to lower it.
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