Do your trees have cedar-quince rust fungus?

Do not mistake this fungus for another related to it called cedar-apple rust or even cedar-hawthorn rust. The fungus starts on needles or branches of junipers or cedars. According to University of Illinois Extension, this rust causes a flaky, perennial swelling on branches rather than round galls. That being the case, the swellings may go unnoticed until they start to enlarge and turn orange.

The symptoms of this fungus can vary from host to host. Branch and thorn infections result in spindle-shaped, perennial cankers that expand each growing season. The branches affected by the canker are girdled and can die in the next season.

This fungus has two hosts that it alternates between to complete its life cycle. After it infects the needles or branches of the cedar or juniper, then it can move onto any number of the 480 species of members within the rose family. Some of these members are apples, mountain ash, flowering quince and hawthorns.

In spring, after the fungus infects the evergreen needles or branches of the cedar or juniper, it sends spores from the developing teliospores found after moisture and cool temperatures around 76 F to deciduous trees just leafing out. These teliospores swell and turn orange, and that is when everyone starts to notice. These teliospores are again not in the shape of round galls, but rather they are orange swellings along a branch.

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