Summer 2019

DutchTrig: A New Vaccine for Dutch Elm Disease

Almstead has partnered with BTL Bomendienst, manufacturers of the vaccine DutchTrig, to treat elm trees in several New York parks against Dutch Elm Disease (DED). Although it has been used in Europe since the early 1990s, DutchTrig is new to the United States. Unlike fungicides, that need to be injected into the trunk flare of trees with pressurized microinjectors (and require root collar excavation and drilling), DutchTrig is injected directly into the stem of the tree just below the bark (into the outermost ring) at chest height. The vaccine consists of fungal spores and water. It is preventative only and cannot cure trees that have already been infected.

DED is caused by a fungus called Ophiostoma ulmi and is spread by bark beetles. The American elm, Ulmus americana, is extremely susceptible and the disease has killed hundreds of thousands of elms across the U.S. since the early 1930s. DutchTrig has been found to be very effective in protecting elm trees on a large scale. It should be applied in spring annually, before Dutch Elm Disease can occur. The vaccine consists of spores of a specific strain of Verticillium fungus that activates the elm’s natural defense mechanism, just like human immunotherapy. Because elm trees grow a new outer layer of sapwood every year, the treatment has to be repeated every spring.

DutchTrig was developed by the University of Amsterdam in the late 1980s but it was approved by the EPA for use in the U.S. only in 2005.  The vaccine needs to be temperature controlled and can only be injected by specialists who have been trained and approved by BTL Bomendienst. Almstead is currently the only partner listed for the New York region. Compared to Arbotect’s tree injected systemic fungicide (another treatment for DED), DutchTrig appeares to be more efficient. Once we have a few seasons of proven care with it, we will look to extend this option to all our clients.

Images: Almstead PHC technician Leo Ibarra (1) and arborist Nick Tripsas (2) receiving training on DutchTrig equipment and treatment. (3) The chisel is designed so that the latest annual ring can be penetrated without penetrating and damaging older annual rings.