''Chrysomyxa ledi'' var. ''rhododendri'' is a plant pathogen responsible for the disease spruce needle rust. It is present in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

an mountains, and especially in

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

Grisons The Grisons () or Graubünden,Names include: *german: (Kanton) Graubünden ; * Romansh: ** rm, label= Sursilvan, (Cantun) Grischun ** rm, label=Vallader, (Chantun) Grischun ** rm, label= Puter, (Chantun) Grischun ** rm, label=Surmiran, (Cant ...

and

Ticino Ticino (), sometimes Tessin (), officially the Republic and Canton of Ticino or less formally the Canton of Ticino,, informally ''Canton Ticino'' ; lmo, Canton Tesin ; german: Kanton Tessin ; french: Canton du Tessin ; rm, Chantun dal Tessin . ...

between 1,000 and 2,000 metres. The

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

s of the fungus hibernate on ''

Rhododendron ''Rhododendron'' (; from Ancient Greek ''rhódon'' "rose" and ''déndron'' "tree") is a very large genus of about 1,024 species of woody plants in the heath family (Ericaceae). They can be either evergreen or deciduous. Most species are nati ...

'' species. In

spring Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of water * Spring (mathematics), a geometric surface in the shape of a ...

and

summer Summer is the hottest of the four temperate seasons, occurring after spring and before autumn. At or centred on the summer solstice, the earliest sunrise and latest sunset occurs, daylight hours are longest and dark hours are shortest, wit ...

, it migrates to

spruce A spruce is a tree of the genus ''Picea'' (), a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. ''Picea'' is the sole genus in the subfami ...

and infects recently emerged needles, coloring them in

yellow Yellow is the color between green and orange on the spectrum of light. It is evoked by light with a dominant wavelength of roughly 575585 nm. It is a primary color in subtractive color systems, used in painting or color printing. In the R ...

. In autumn, the spores that developed on spruce infects the rhododendron again.

References

Fungal plant pathogens and diseases Fungi described in 1815 ledi var. rhododendri {{Teliomycotina-stub