Gymnosporangium clavipes Cke. & Pk.
Quince rust produces swellings rather than galls on red cedar. It has been known to attack Delicious, McIntosh, Winesap, and Yellow Transparent apples, producing dwarfing, distortion at the calyx end, and an internal discoloration which penetrates the fruit tissue much deeper than apple-cedar rust does. Aecia and pycnidia may develop, but are not usually produced. Only occasionally do affected fruits reach the market. The affected surface tissue is deeper green (see photo) than the normal skin color, instead of yellow like that affected with apple-cedar rust.
For control follow the recommendations of the State agricultural extension service or experiment station.