I'll just add that my serviceberry tree also has something going on with it that might be the same thing.

Plus, if my original post gets a reply, maybe it won't stay stuck to the very top of the page. It's lonely at the top.

I have 2 quince trees (one Smyrna and one Aromatanaya) and have never had any problems with fungal diseases. In fact, they seem to be the easiest trees in the orchard with regards to pest problems. I have seen leaf edges turn brown, both on quince and on pears, when there was a late frost after the leaf buds had broken.

According to the PNW Disease Management Handbook used in Extension Service offices of the NW, quince are subject to all the problems that afflict pears.

As for the serviceberry, they commonly get rust.

My quince tree gets varying amounts of leaf spot every year whether I lime-sulphur it in winter or not. Some of the quince fruits have the same spotting, but it is minor compared to leaves. Tree still looks fine. Have never seen actual leaf shriveling.

My Quince trees have a lot of brown leaves and deformed fruit.
What do yhou recommend for a spray or other treatment