Dutch Elm Disease (DED)

Dutch elm disease is a fatal disease of elm trees caused by the fungus, Ophiostoma novo-ulmi. This fungus grows only in elm trees and is responsible for the death of millions of elms.

Originally from Asia, the Ophiostoma novo-ulmi fungus was imported to Europe, where Dutch researchers were the first to isolate it (hence the Dutch elm disease name). It was later imported into the United States where it has spread throughout its range of native elms, and is now also widespread throughout Canada.

Arboris Inc. | Experts in DED management

Our team has many years of experience dealing with Dutch Elm Disease. Arboris has treated thousands of elms in the region... from Kanata to Québec City we have become the reference in DED management.


Arbotect® 20-S is a systemic fungicide formulated with Thiabendazole and is applied through a process called macro-infusion. Arbotect 20-S is the only scientifically proven fungicide that provides multi-year protection from Dutch Elm Disease. Arbotect® 20-S is now available in Canada.


Tracing is a method of saving elms recently infected with Dutch elm disease. It is far more cost effective than removing and replacing an elm. By utilizing this procedure, a city can save many thousands of dollars. Since the fungus that causes Dutch elm disease grows very predictably in a narrow band downward and only in the current year’s water-conducting vessels, tracing is possible and was proved to be effective.


The only way to stop the spread of Dutch elm disease through root grafts is by physically breaking the root connections between the infected tree and the healthy tree. This is most often accomplished with trenchers or compact excavators. In situations where there are buried utilities, an Air Spade can be used to remove the soil and expose the root grafts without damaging the utility lines.

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