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Basidia, in turn, produce inoculum, called basidiospores, which will germinate followed by infection of spruce needles. Release of basidiospores coincides with new needle emergence on spruce trees. Dispersal is facilitated by wind and rain, which can carry these spores to other parts of the same tree, or to nearby trees.
Norway spruce is a large, fast-growing evergreen coniferous tree growing 35–55 m (115–180 ft) tall and with a trunk diameter of 1 to 1.5 m. It can grow fast when young, up to 1 m per year for the first 25 years under good conditions, but becomes slower once over 20 m (65 ft) tall. [ 6 ]
The plant pathogenic fungus Leucostoma kunzei (formerly Valsa kunzei) is the causal agent of Leucostoma canker (also known as Cytospora canker or spruce canker), a disease of spruce trees found in the Northern Hemisphere, predominantly on Norway spruce (Picea abies) and Colorado blue spruce (Picea pungens).
The leaves are needle-like, the shortest of any spruce, 6–8 mm long, rhombic in cross-section, dark green with inconspicuous stomatal lines. The cones are slender cylindric-conic, 5–9 cm long and 1.5 cm broad, red to purple when young, maturing dark brown 5–7 months after pollination, and have stiff, smoothly rounded scales.
The unilarval chambers are set in a woody core. The stem and needles of the host can continue growing beyond the position of the gall. [5] Sitka and Norway spruce are the main hosts, but A. abietis galls can be found on Colorado blue, white, and red spruces. The yellowish green galls pass through pink and then reddish-brown colour phases.
The mites feed on the cell sap of the tree's needles, sometimes causing severe damage. [5] Typical effects from a Nalepella infestation include needle discolouration and premature needle drop. [ 3 ] [ 7 ] The colour of discolouration varies by species; for example, Nalepella tsugifoliae causes yellowed or grey discolouration, while Nalepella ...
Old Tjikko [a] is an approximately 9,567-year old Norway spruce, located in the Dalarna province in Sweden. Old Tjikko originally gained fame as the "world's oldest tree". [1] Old Tjikko is, however, a clonal tree that has regenerated new trunks, branches and roots over millennia rather than an individual tree of great age.
The yellow-headed spruce sawfly, Pikonema alaskensis, is widely known in the northern United States and Canada as a destructive pest of spruce. [1] It attacks white, black, Norway, and Colorado blue spruces. The larvae at first prefer new foliage, but after becoming about half-grown, old needles are included in their diet too.
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