Cedar Apple rust

Asked May 30, 2018, 10:32 PM EDT

We just noticed hundreds of orange spores on our juniper tree, which is 20 feet from our crab apple, which had yellow/ brown leaves last year that dropped off early. We are desperate not to lose these trees. What can we do? Please help.

Dakota County Minnesota cedar apple rust horticulture

1 Response

It is possible that the yellow/brown leaves on the crab may be simply apple scab, a common fungal disease of apples. The rust spots from cedar-apple rust are quite distinctive. Both diseases (cedar-apple rust and scab) rarely require management (on either host, in the case of cedar-apple rust). You are unlikely to "lose" your trees.

Read here about apple scab:
https://www.extension.umn.edu/garden/yard-garden/fruit/apple-pest-management/apple-scab/

Removing the associated galls on the juniper is one management strategy for cedar-apple rust. But the short answer is that one should avoid planting these two trees near one another. Read here about cedar-apple rust:
https://www.extension.umn.edu/garden/yard-garden/fruit/apple-pest-management/cedar-apple-rust/
https://www.extension.umn.edu/garden/yard-garden/trees-shrubs/cedar-apple-rust-and-gymnosporangium-r...