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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.
Picea abies, the Norway spruce [2] or European spruce, [3] is a species of spruce native to Northern, Central and Eastern Europe. [ 4 ] It has branchlets that typically hang downwards, and the largest cones of any spruce , 9–17 cm long.
The peg-like base of the needles, or pulvinus, in Norway spruce (Picea abies) Pulvini remain after the needles fall (white spruce, Picea glauca) Determining that a tree is a spruce is not difficult; evergreen needles that are more or less quadrangled, and especially the pulvinus, give it away. Beyond that, determination can become more difficult.
Chrysomyxa abietis, or spruce needle rust, is a species of rust fungi in the Coleosporiaceae family that is native to eastern Europe (including Siberia) and northern Asia. [2] It was introduced to Australia , New Zealand and the United States .
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).
It has a narrow conical crown. The leaves are needle-like, yellow-green, 12–15 mm (15 ⁄ 32 – 19 ⁄ 32 in) long, four-sided, curved, with a sharp point, and extend from all sides of the twig. The bark is gray-brown on the surface and red-brown on the inside, thin, and scaly. The wood is light, soft, has narrow rings, and has a slight red ...
The symptoms give the disease its name. The first signs of infection that can be seen are yellow and brown spots that develop on the living needles, [7] [8] which soon turn red. This infection starts on the base of the crown on older needles, which then turn a brownish red at the tip, while the rest of the needle remains green. [9]
They infest fir, hemlock, larch, and yew to high densities- there may be as many as 100 mites on one needle. [3] [7] [38] Infested trees turn bluish, then yellow, before beginning to drop needles. [39] They feed on both sides of the tree's needles. [40]