Monday, May 30, 2016

May 27, 2016: Cedar-Apple Rust

Many of the Eastern Red Cedars (Juniperus virginiana) along the Upland Trail are infected with Cedar-Apple Rust (Gymnosporangium juniperi-virginianae).  This fungus has two hosts: cedars/junipers and apples/crabapples.  In late Spring, brown galls that have been hanging on cedar limbs all Winter begin to become more gelatinous and grow orange tentacles.  Spores are released by these tentacles and when they land on apple trees, they start the next phase of their complicated life cycle.  These spores can travel 2 to 3 miles on the wind.  On the apple trees the spores will grow into rust-colored spots on the leaves or apples.  These spots are actually cup-shaped structures full of new spores.  These spores stick to insects that will transport them to new cedars, where they will grow into a hard, brown ball, starting the process all over again. 5/27/16 (Wolf. Oesterreich)

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