Cedar Apple Rust – Identified

Q: I have two seven-foot tall Eastern red cedar trees. Both have growths that look like walnut meats on them. Is this cedar apple rust?

A: Orange, jelly-like spore “gobs” were on the trees last spring but you didn’t notice them. The gall you notice now will be at the center of the fist-sized mass in April-May. This particular disease travels back and forth between Eastern redcedar and apple trees. Both hosts are required for it to develop.

Cedar apple rust is less harmful to redcedars than apples, on which it causes leaf and fruit drop. If you value woodland apples and crabapples, remove all of the dried galls now.

The disease can be managed on apple by spraying with Immunox® Multi-Purpose Fungicide Spray Concentrate For Gardens. Spraying with myclobutanil (Immunox) at labeled intervals will partially control the disease. You can help break the disease life cycle by raking and removing all apple leaves after they fall in winter and by examining all redcedar trees in your neighborhood for the walnut-sized disease galls, which should be destroyed. Read and follow label directions.


Cedar Apple and Related Rusts

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