Answer: Classic symptoms of Dutch Elm Disease include yellowing, wilting and browning of leaves on individual branches, which eventually die. If you strip the bark from such a branch you will see brown streaks in the sapwood. If the leaves of your trees are only showing brown margins, I think the problem is leaf scorch, either from overexposure to sunshine, or from over-application of fertilizer. (Pruning a tree when it's in full foliage can expose previously shaded leaves and branches to more sunshine than they're used too, and can result in sunscald.) It's late in the season and the leaves will begin to fall soon. Rake them up and remove them from the garden. Next spring new foliage will emerge and should look healthy. Best wishes with your elm trees!
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