Leaf Rusts

Leaf Rusts of Hardwoods and Needle Rusts of Conifers

Poplar Leaf Rust -Melampsora medusa

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Uredinia are formed on the bottom of leaf. They arrear as small yellow fruiting bodies called sori. These produce urediniospores that reinfect poplars

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Uredinia sori on leaf viewed with a hand lens.

Uredinia of poplar leaf rust

View of the uridinia using a stereoscope.

Poplar leaf rust telia

Later in the season, telia form on the bottom of leaf at sites where the uredinia were located.

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Telia appear as hardened dark fruiting bodies. The teliospores are embedded in the telium which is in the leaf.

diagram of telia in leaf

Diagram showing teliospores in the leaf and basidiospores being produced. The basidiospores infect larch.

poplar leaf rust spores

Two leaves as seen under the sterioscope. A leaf with uredinia is on the right and a leaf with telia is on the left.


Red Pine Needle Rust -Coleosporium asterum

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Aecia on red pine needle (pycnia was present a few weeks eariler).

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Uredinia and telia on golden rod leaves. Another alternate host is aster.