We have 3 thirty year old pear trees, all on semi-dwarf root stock. The trees are Orcas, Bartlett and Bosc. Over the past 5 or so years we have seen increasing amount of rust on the foliage. This year all leaves are showing the spotting from rust with roughly 20% of the surface areas of each leaf infected. Last year the pear crop was very small - perhaps 200 pounds when normally we get around 500 - 600 pounds total for the 3 trees. This year the crop will likely be less than 100 pounds. I have looked at other European pear trees in our area in Portland. My suspicion is that fruit pollination was poor due to weather conditions at the time of bloom. I do not know if the rust affects fruit set. Most information I read does not give any clear instruction on means to manage rust when using organic practices. Does this severe level of rust affect fruit set on pears? What means are recommended to reduce the level to rust on these three trees?