I see that my small tree does show signs of Cedar-Quince Rust on a few of the fruits so this plant is not as disease free as sometimes claimed. The forest around my property has a few Eastern Red Cedar or juniper trees and the list of fruiting plants that suffer from one of the many forms of Rust disease keeps growing. I've seen Cedar-Apple Rust, Cedar-Quince Rust and Cedar-Hawthorn Rust so far and it affects pears, serviceberries and now medlar. Some plants only show a little damage but others are killed by it.