Cedar-quince rust is a fungal infection that operates with two host plants. The Primary hosts of this fungus are typically evergreens like Junipers and Cedars. The Alternate hosts are found among Apples. Quince, Hawthorn, and other members of the Rose family. This includes Pears which typically do not suffer from this infection, however the conditions have been ideal for this to spread as of late. Asian Pears are known to be resistant to this kind of fungal infection. Spores created by this fungus are carried by wind and rain to unsuspecting fruiting trees and result in tiny orange to pinkish fungal “tubular” like growths on the fruit called aecia.

Symptoms can vary depending on the host plant and conditions. Primary hosts can exhibit swelling on branches and twigs and eventually dieback can occur after some orange-like substance bursts from the swellings. Branches can be infected for years until ideal conditions persist.

Alternate Hosts exhibit more obvious symptoms such as the fruiting and branches will show the telltale sign of aecia and an orange blister like rust on the younger branches. Fruit and young branches are more susceptible to symptoms than leaves. On Hawthorn, thorns can display symptoms as well.

It’s important to remember this disease is not lethal, but can minimize or halt fruit production for the year. A holistic approach is needed to manage this fungus. Removed infected material of both primary and alternate hosts can be beneficial. Preventative pruning of the primary host is good, but does not remove all inoculants. Fungicide applications of Captan, Daconil and Mancozeb have been shown to work. For Treating Primary hosts, the best time to apply is the start of spring when the plants are actively growing.