Cedar-Hawthorn Rust

Most noticeable on Hawthorn trees, this disease also infects Crabapples, Apples, and sometimes Serviceberry and Pear trees. The disease is most noticeable because of the small orange “dots” that appear on the leaves of the plants. This disease rarely kills a Hawthorn tree, but it can disfigure infected twig and branches. In order to survive, this disease actually requires two host plants to transfer between, the Hawthorn tree and the Juniper evergreen.

What Does Cedar-Hawthorn Rust Look Like?

Small orange circles will speckle the leaves after infection in the spring. As the disease matures, the circles will get larger and smaller black centers appear in the orange circle. By summer, there will be 1/8” tubes hanging from the underside of the leaves. In a severe infestation, the leaves also may turn bright yellow and fall off early.

More Detailed Information About Cedar-Hawthorn Rust

Cedar-Hawthorn rust is caused by a fungus called Gymnosporangium globosum. There are actually three kinds of Cedar-Rust, also including Cedar-Apple Rust and Cedar-Quince Rust, all of which are closely related Rust diseases.

Rust diseases have five different spores in their life cycle, with no repeating spores. Which means the disease doesn’t re-infect the same plant, or at least not for several years.

Treatment Of Cedar-Hawthorn Rust

Treatment is a preventative spring-only fungicide application that should be made before or during the bloom cycle. For an estimate to treat your Hawthorn trees for Cedar-Hawthorn Rust, please call our office or request a quote online.

Plants Susceptible To Hawthorn Rust In Chicagoland

• • • Eastern red cedar
    • Rocky Mountain Juniper
    • Southern Red Cedar
    • Common and prostrate junipers
    • Apples
    • Crabapple,
    • Hawthorns
    • Pear
    • Quince
    • Serviceberry.