My "Korean Giant" produced a couple of fruits last year but this is the first year it has a decent crop. Unfortunately, I checked them and all the fruits are covered with rust. My ornamental quince also gets this; my Dolga and Hopa crabapples are not affected.

So much for Asian pears being a no spray fruit crop here! (Although I do dormant oil sprays in the winter anyway.)

Other than instructions to remove all cedars within a mile, which is not even remotely possible, or to spray with fungicides, I've been unable to find instructions on timing the fungicidal spray to control rust or fungicide selection.

Assuming a general purpose fungicide like lime sulfur will work, when and how often do I need to spray?