July 2, 2008
Cedar-Apple Rust, Gymnosporangium juniperi-virginianae
on the fruit of a Shadbush, Amelanchier canadensis
This orange fungus spends part of its life cycle on a Juniper host and
part on a host in the Rose Family (which includes Amelanchiers). It
requires both hosts to complete its life cycle. This year all of the
Amelanchier trees on the Reservation have been affected. Normally the
fruit, when ripe, are shiny, almost black, and a delicious treat for
birds, humans, and other animals.
Next year the fungus will jump to the Red Cedars, Juniperus virginiana,
causing the same orange growths, and making those berries inedible for
birds.