Early diagnosis can help save recently infected trees. Look for branches with leaves that have wilted and suddenly turned yellow to brown. Remove a portion of the branch and peel back an area of the bark. If you notice brown streaking in the sapwood, you may have Dutch elm disease. Healthy bark is more cream-colored and the streaking is absent. Suspect wood should be submitted to the diagnostic lab and control measures started immediately.
Dutch elm disease can often be controlled through the use of systemic fungicide injections, judicious pruning of affected trees and removal of nearby diseased elms. However, trees infected through root grafts with nearby infected elms or those in which the disease has reached the main stem cannot be saved. Therefore, preventative measures have a better chance of success and are preferred. Fungicides labeled for Dutch elm disease include Arbotect and Alamo. The Arbotect fungicide is preferred because it is the most persistent with a three-year interval between injections. Alamo may need to be applied every year in high risk areas with high value trees. A trained arborist should administer injections. These treatments are quite expensive. Check with your local arborist for current prices.
Megan Kennelly, one of our plant pathlogists, has a more detailed discussion of this disease in our Turf Blog. See http://blogs.k-state.edu/turf/dutch-elm-disease/ (Ward Upham)