Has any progress been made to find an inoculant to protect these grand old elms trees from Dutch elm disease? How effective are products? Can I purchase them and treat trees in my neighborhood? What are the costs? Do I need special equipment and training? What do private companies charge to do the work?
Minnesota Master Gardeners say:
Sanitation remains the single most important and effective weapon in the battle against Dutch elm disease (DED). Once a tree has DED, fungicide treatment is usually ineffective. Systemic fungicide should only be used to protect healthy specimen trees. It should only be applied by a qualified arborist and treatment is quite expensive and must be repeated every one to three years. Repeated treatment (injections into the tree collar) may eventually injure the tree. Be very wary of untrained or unscrupulous individuals in competition with trained arborists.
