| dc.description.abstract | Various aspects of the biology of Chondrostereum
purpureum (Pers.:Fr.) Pouz. and its role in dieback and
decline of white birch (Betula papyrifera Marsh.) were
studied. (1) Sixty-nine trees which exhibited symptoms of
dieback and decline were sampled for C. purpureum infection
in Thunder Bay, Ontario. Using a variety of sampling
methods, including boring, and trunk and branch dissection,
C, purpureum was isolated from 26 (38%) of 69 trees
sampled. The increment borer sampling technique proved to
be the most efficient method of isolating the pathogen, in
terms of combining ease of execution and good success rate.
(2) The pathogenicity of C. purpureum to birch seedlings
was tested. All twenty—six seedlings infected with
mycelium developed open wounds, 12 of which cankered,
whereas the wounds in 26 controls closed within 4—6 weeks.
Progress of the infection varied. Spread of the canker
from the wound site (including stem girdling and dieback in
two seedlings), spread through the xylem and formation of
cankers further up the stem, and apparent containment of
the infection at the wound site were observed. (3) The
properties of white needle-like crystals which formed on
heavy spore casts were investigated. The filamentous
crystals were composed of a sesquiterpene compound
(Cj^gH2gO, M^ 222, m.p. 136°C) similar to ( + )-torreyol . (4)
The"^sexual ity of C. purpureum was investigated. The fungus
is heterothal1ic, with tetrapolar sexual differentiation.
Anomalies such as unilateral compatibility and unequal
abundance of clamps and fruiting in compatible pairings
were observed. (5) A method of inducing growth of C.
purpureum basidiocarps and their storage was devised. | |
