Symptoms and signs on white pine

Rusts

White Pine Blister Rust - Symptoms and Signs on White Pine

blister rust canker

A blister rust canker in the field showing the canker lesion and resin exuding from the infected stem. Note the branch at the center where the infection entered the main stem.

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Canker on the main stem of white pine with resin oozing out.

Blister rust pycnia

Young blister rust cankers. Pycnia would be produced on these cakers in the spring.

Rodent chew of blister rust

Areas on the cankers that produce pycnia are often chewed by squirrels and rodents. They are attracted to the sweet pycnial fluid that oozes out of the pycnia.

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Aecia on canker of white pine.

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The blister-like aecia have a white peridiurm that ruptures to release the aeciospores.

Aeciospores

Aeciospores viewed with a microscope. Aeciospores have rough warty projections.

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Another microscopic view of aeciospores. Note rounded projections on spores.

Blister rust aeciospores

A scanning electron micrograph showing the warty appearance (rounded projections on the spore) of an aeciospore

Tuberculina on blister rust

Purple mold, Tuberculina, attacking the rust fungus on two branch cankers.