Dutch Elm Disease
Emerald Ash Borer, dutch elm disease, maple wilt, disease control, tree treatments
Dutch elm disease is one of the well known diseases in Minnesota. Many people remember these trees lining the streets of many cities, including Minneapolis.  This fungal disease has killed off millions of tree; There are still an estimated 1 million American elm trees left in Minnesota. Dutch elm disease was first discovered in Minnesota in 1961, and still exists to this day.  Many elms that can be found in the metropolitan area have been preserved with chemical treatments.

Disease cycle

Dutch elm disease is made up of two different fungi.  It is spread in many different ways, including: root grafting, insect (vector) spread, and spores from cankers.  When the pathogen enters the tree it starts to multiply rapidly.

The picture on the top right shows the first signs that are noticed in a tree as it starts "flagging" the disease.  From here the disease infests the cambium layer and spreads through the entire tree.  This process restricts flow of nutrients, water, and sugars throughout the tree.  The picture on the bottom right show the streaking where the fungus was growing in this section of an American elm.


Dutch elm disease has been treated for 30 plus years using an active ingredient called propiconazole.  The most effective treatment method is via trunk injection.  Most other methods have little to no success treating this disease.  Treatment timing should be done ASAP, as the disease kills a tree very fast.  Once a tree is affected by Dutch elm disease the homeowners may only have a few days to make a quck decision.

It is possible to treat trees that have just contracted Dutch elm disease, but the diseased areas need to be cut out completely and the tree treated immediately via trunk injection.  Arbor doctor provides the best Dutch Elm Disease treatments on the market by Arborjet!