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Spruce Needle Rust

Spruce needle rust; this fungus is on the needles of spruce trees one half of the year and the other half on plants of the heather family.

Do not confuse with:
Coleosporium tussilaginis

recognize spruce needle rust
Spruce needle rust, photo: Tappinen - CC BY-SA 3.0

Spruce needle rust (Chrysomyxa spp) – a family of rust fungi (Pucciniales). Some of these fungi spend half the year on the needles of spruce trees and the other half on plants of the heath family (Ericaceae). Both spruce and Ericaceae species are host plants of spruce needle rust (Chrysomyxa abietis).
In spring with cool weather and lots of wetness, the spores originating from the Ericaceae species infect the young formed needles of the spruce trees. In summer, the fungi form orange powder-like spores. These infect the Ericaceae species.
In autumn, the infected needles yellow and then fall off.
Spruce needle rust hibernates in the branches of spruce and in Ericaceae species.
This fungus can also cause a single witch’s broom in the spruce.

Where to find

  • Blue spruce (Picea pungens)
  • White spruce (Picea glauca).
  • Black spruce (Picea marina).
  • Norway spruce (Picea abies)

Control

This fungus does not pose a major threat to the health of the spruces and does not need to be controlled.

Prevention

Spruce needle rust infestation is mainly cosmetic: it is not a pretty sight all those yellowed needles.
To avoid infection with the fungus, provide a location where the wind has free play. And remove witches’ brooms.

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