sdu faculty of forestry journal special edition 2009 - Orman Fakültesi

4. DISCUSSION
SDÜ ORMAN FAKÜLTESİ DERGİSİ
In this study, T. areolata and C. pirolata, which are causes for severe rust
epidemics in Finland, fruited and sporulated in young current-year cones the next
year after a serious rust outbreak. The high incidence of T. areolata aecia in
previous year’s cones confirmed that it was the main cause for the serious rust
outbreak in the study areas in 2006. In all stands, T. areolata uredinia and telia
were frequent on both overwintered and current-year P. padus leaves indicating
that alternate host infection took frequently place both in 2006-2007. The high
disease incidence coincided with the incidence of aecia in previous year’s cones,
too. In this study, T. areolata aecia sporulated mainly in one-year-old cones as
reported (Jørstad, 1925), but single sporulating aecia could be found already in late
summer after infection. The observed aeciospore and urediniospore size and
morphology was in accordance with the reports elsewhere (Gäumann, 1959; Saho
and Takahashi, 1970). As practically all scales in infected cones bore T. areolata
aecia, the rust was highly pathogenic and systemic in the cones and hindered
efficiently seed formation.
The occurrence and morphology of spermogonia, spermatia, aecia, aeciospores,
uredinia, urediniospores, telia and basidia of C. pirolata corresponded well to
earlier reports (Gäumann, 1959; Sutherland et al., 1984; Crane and Hiratsuka,
2000). As most scales in infected cones were covered by C. pirolata aecia, the rust
was highly pathogenic and systemic in cones. Therefore, the rust had a great
impact on cone development causing seed deformation in diseased cones. The
gelatinuous young fruiting structures, undifferentiated fruitbodies, corresponded to
those described previously (Crane and Hiratsuka, 2000), and reported to develop
either into uredinia or telia depending on the amount of moisture and free water.
5. REFERENCES
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