Question
Can Dutch Elm disease kill crepe myrtles?  And if a tree dies from dutch elm, would other trees (albeit different species of elms) also be affected if they were within 10 feet of each other?  I have 3 trees (chinese elms) that have died (1 in front and 2 in back).  They are surrounded in the back by very healthy lace elms.  We have used a lawn service to spray for weeds and growth and this year our trees (and only our trees) did not come back.  The lawn service says it is b/c of dutch elm disease, however, an arborist suspects accidental herbicide poisoning.  Just trying to get an unbiased answer as I think the lawn service manager is not telling me the truth.

Answer
Dutch Elm Disease is typically spread by beetles.  You will see scaring on the bark of the tree.   Little lines that were made by actual beetles carving through the bark.

With out inspecting your trees I really cant tell you.  But I can tell you that I have run a commercial landscape company for about 11 years and I have had lots of employees kill alot of plants with glysophate (round up).

The one thing that confuses me is that the lawn man would have had to be spraying up in the air as you are talking of a tree.  Unless your trees are very young and low to the ground.  Round up has to touch the green leaves to kill.  It really does not work through the bark unless you really really soak it.

James