Here are the photos you requested. I probably over-reacted. The spots are present on only 2 trees. Everything looks healthy. The cherries and pears are setting fruit.
Pears are prone to several fungal leaf spot diseases--pear scab, fabraea leaf spot, and entomosporium leaf spot. I would need closeup pictures of the top and bottom of the leaves with the spotting to make a firm diagnosis. However, my hunch is that most of it, especially the clusters of round spots, is fabraea leaf spot. This will likely continue to spread this season, but it is difficult to predict if it will progress to the point that some leaves tdrop. Fabraea is relatively easy to control with fungicides if primary infections are prevented during the period from Petal Fall through June. Mancozeb and Ziram are the most effective fungicides for controlling Fabraea and the other two diseases. Tree fruit will tolerate some leaf spotting & leaf loss, so you can use your experiences this year to judge what you want to do in other years.
Thanks for all the info on fungicides. I think that we are going to take your advice and just watch the trees this year. And decide what to do next spring. I'll be in touch and probably will ask a few more questions as we get closer to a decision on whether to spray or not. Thanks again, Stewart Gordon
