sdu faculty of forestry journal special edition 2009 - Orman Fakültesi

SDÜ ORMAN FAKÜLTESİ DERGİSİ
The identity of the pathogen was confirmed as D. pinea. Eleven of the 12 filters
that were tested were positive for this fungus. The test of one filter produced no
result. No filters tested positive for D. scrobiculata.
The estimated numbers of conidia extracted from galls (when expressed on the
per gram odw basis) often were within the range or even greater than numbers
reported by Munck and Stanosz (2009) for pine cones. In that study, cones from
which D. pinea (or less frequently D. scrobiculata) were cultured were collected
from the crowns of red pines (P. resinosa Aiton) and jack pines (P. banksiana
Lamb.) in which typical shoot blight symptoms were not apparent. The greatest
mean number of conidia extracted per gram odw for any of these locations was
23,181, for cones from red pine crowns. The large numbers of conidia obtained
from Cooley spruce gall adelgid galls indicate that, at least in this case, inoculum
production by D. pinea is not limited by its exploitation of an atypical host as
substrate.
Previous researchers have noted a diversity of relationships between D. pinea
and insects or host material altered by insects. Epidemics characterized by severe
damage to Scots pine (P. sylvestris L.) in Ontario was associated with injuries
resulting from feeding of the pine spittle-bug (Aphrophora parallela Say) (Haddow
and Newman, 1942). In contrast, Feci et al. (2003) found D. pinea only
infrequently on red pine shoots damaged by insects, primarily the red pine shoot
moth Dioryctria resinosella Mutuura. Other studies provide evidence that the cone
bug Gastrodes grossipes De Geer has a role in movement of this fungus to cones of
Austrian pine (Feci et al., 2002) and support the conclusion that the bark beetle Ips
pini (Say) may vector D. pinea (Whitehill et al., 2007).
Researchers also have noted a previous relationship between an apparent
disease and adelgid galls on spruce. Audley and Skelly (1994) noted the
occurrence of necrotic twigs of red spruce (Picea rubens Sargent) that bore galls of
the eastern spruce gall adelgid. A Phomopis Harter species was isolated from 14 of
33 dying, adelgid-galled twigs. This fungus was used to inoculate seedlings, and
produced cankers in 29% of the attempts.
Documentaton of the sporulation of D. pinea on insect altered, necrotic spruce
tissues does not clarify the potential confusion about the ability of this fungus to
infect and kill normal spruce shoots under natural conditions. Although spruces
are included on lists of trees on which D. pinea has been reported (Farr et al., 1989;
Punithalingam and Waterston, 1970) such sources do not provide details necessary
to know if the fungus was causing disease or merely was present saprophytically.
Interpretation of reports of D. pinea from spruces is further complicated by current
knowledge that past references to D. pinea sensu lato may have referred to either of
two species (i.e., D. pinea or the similar fungus D. scrobiculata that was described
by deWet et al., 2003). For example, Myren (1991) attributed killing of stems and
branches of stressed black spruce (P. mariana (Mill.) B. S. P.) in an Ontario seed
orchard to D. pinea (as S. sapinea). However, isolates later collected from black
spruces at that seed orchard and each of four other Ontario seed orchards all were
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