6 Wood Discoloration

124 6 Wood Discoloration
bark. Pulpwood handler’s disease is caused by Alternaria species growing on
paper pulp. Farmers inhale spores of Aspergillus fumigatus when damp hay
is worked. Dustmen and compost makers may be exposed to molds when
kitchen waste is stocked in closed containers for too long. Mushroom growers
may be exposed to huge quantities of spores released by the basidiomycete
they cultivate, and the culture substrate is sometimes contaminated by molds
(mushroom grower’s disease) (Nolard 2004).
Superficial mycoses occur on mucous membranes (fingernail bed, lips) and
profound mycoses after wounding the skin or inner body (ear, eye, lung, blood
vessels). Deuteromycetes are also significant in view of immunodepression in
cases of transplants and of diminished defense mechanisms of AIDS sufferers.
With regard to indoor environments (Frössel 2003; Hankammer and Lorenz
2003) only a few molds are considered as producers of important toxic compounds
which can be released in the environment and which may cause severe
health problems (Samson and Hoekstra 2004). These are Alternaria alternata,
Aspergillus flavus, A. fumigatus, A. versicolor, Chaetomium globosum, Emericella
nidulans, Memnoniella echinata, andStachybotrys chartarum, whereby
the latter is considered the most important toxic fungus in buildings producing
the cytotoxic satratoxins. A questionnaire study among U.S. homebuilders,
new homeowners, and real estate agents indicated that overall, respondents
did not have a strong understanding of how mold forms in new constructions.
Ten percent of homeowners believed that mold was an issue in their neighborhoods
while 35% of home builders and 19% of real estate agents believed
that this was an issue in the homes they built (Vlosky and Shupe 2004). The
aspect of molds on indoor piled chips was treated by Feicht et al. (2002). Air
sampling is performed to quantify and identify contamination. Measurement
of microbial volatile organic compounds (MVOCs) in houses serves as note
for contamination, especially for hidden contaminations (Keller 2002). Stachybotrys
chartarum and Chaetomium globosum emitted ketones and alcohols
(Korpi et al. 1999). There are also dogs trained to detect molds by sniffing.
For remediation, first of all the cause of the damage (dampness) has to be
removed continuingly (Neubrand 2004). In view of allergies, the spores may
be taken away. There are primers and paints with prophylactic anti-molding
substances, like organic sulfur-nitrogen compounds (thiocarbamate) and organic
tin compounds (tributyltin oxide). Yang et al. (2004b) proposed that
incorporating tree bark (white spruce), which inhibited mold growth in vitro,
into the production of composite boards may increase the resistance of panels
to fungi.
Particularly several Trichoderma species are antagonistic against other organisms
and also destroy (mycoparasitisms) fungal parasites and saprobionts
(v. Aufseß 1976; Highley and Ricard 1988; Murmanis et al. 1988; Giron and Morrell
1989; Doi and Yamada 1991; Dumas and Boyonoski 1992; Phillips-Laing
et al. 2003).
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