Fir Broom Rust

Leaf Rusts of Hardwoods and Needle Rusts of Conifers

Juniper Broom Rust - Gymnosporangium nidus-avis 

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Juniper with witches' broom.

Juniper broom rust telia

The telia form firectly on the needles. This photo shows the telia (dark areas) when dry.

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Telia on branches from a juniper broom during wet weather. The telia have expanded producing a gelatinous mass which contains the teliospores.

Service berry with rust

Serviceberry, Amelanchier, is the alternate host for Juniper Broom Rust.

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Pycnia are produced on top surface of Amelanchier leaves.

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Aecia are produced on the bottom of Amelanchier leaf. The aeciospores infect junipers

Fir-Broom Rust

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Melampsorella causes a withches' broom on fir. The alternate host is chickweed (photo not shown).

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Pycnia and aecia are produced on needles of the broom on balsam fir.

pycnia and aecia of fir broom rust

A view through the stereoscope showing a needle with pycnia (black dots) and aecia (white structures that produce aeciospores).