Warmer air and rain were in the forecast. I did not notice anything unusual on the Eastern Red Cedar (Juniperus virginiana) trees when I pulled out of the driveway. On my return and after a gentle rain had fallen most of the day, it looked as if someone had decorated the cedar trees with tiny, orange starburst-shaped ornaments. The Cedar-Apple Rust Galls (Gymnosporangium juniperi-virginianae) had matured and were setting out spore.
Cedar-Apple Rust is a fungus that spends part of its life cycle on apple and crabapple (Malus spp.) trees and and part of its life cycle on Eastern Red Cedar trees.
When early rains of spring arrive, the Cedar-Apple Rust Galls produce elongated jelly-like horns that produce spores. The spores travel by wind to susceptible apple trees.
The spores attach themselves to undersides of young apple leaves creating orange-red dots. Later in the season, the lesions on the apple leaves produce spores that travel by wind back to susceptible Eastern Red Cedars.
