When trees are cut fungi can rapidly colonize the
sapwood and cause a dark stain. This stain often appears blue or
black and reduces the quality of the wood. Blue stain in pine and
other coniferous woods is very common but dark stains also form
in hardwoods like maple, birch and beech. The aggressive sapstaining
fungi that cause the stain are very difficult to control and in
the past chemicals such as pentachlorophenol have been used to protect
cut wood surfaces from stain. Our research has focused on a new
approach to controlling sapstain using biological control. Naturally
occurring albino strains of Ophiostoma are being tested
to control dark staining fungi. The biocontrol agent is applied
immediately after cutting and as it grows in the wood it captures
nutrient resources that stain fungi normally use. Since the fungus
is colorless, there is no stain caused by the biocontrol agent.
Once established, the albino strain effectively prevents subsequent
colonization by fungi that cause dark stains in wood. Field testing
is underway in New Zealand (in cooperation with Professor Roberta
Farrell, University of Waikato, Hamilton, New Zealand) and in Chile
(in cooperation with Professor Jose Navarrete, University of Bio-Bio,
Conception, Chile) using Pinus radiata. This tree grows
very fast in these countries and consists mostly of sapwood which
is severely affected by blue stain fungi.
Pioneer colonizing white rot fungi are also being
used as biological control agents to prevent stain in wood used
for pulp and paper production. Fungi such as Phlebiopsis gigantea
(previously called Peniophora gigantea) have been used
to treat pulpwood during shipping and storage. The treatment prevents
stain fungi and causes beneficial changes in the wood that helps
to facilitate the pulping process (such as reduced energy use during
mechanical pulp production and improved paper qualities).
For more information see the following pdf files
of published papers:
Survey of sapstain
fungi on Pinus radiata in New Zealand
Albino
strains of Ophiostoma species for biological control of sapstaining
fungi
Biological
processing of pine logs for pulp and paper production with Phlebiopsis
gigantea

Fungi, such as the albino strains used for biocontrol, out
compete wild type fungi that cause dark stains and prevent them
from colonizing the wood.
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Blue stain in pine

Blue stain occurs during transport and storage of cut wood and is
often associated with bark beetles

Biocontrol field trial in New Zealand

Wood chips treated with biocontrol fungus before
pulping
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