Dutch Elm Disease

Dutch elm disease (DED) is caused by a fungus called Ceratocystis ulmi. It is transmitted from infected trees to healthy trees by the European elm bark beetle, which occurs in many locations within B.C.

Symptoms of the disease first appear in June or early July. Leaves wilt, yellow and turn brown in the summer, often on one side of the tree. This is followed by dieback of branches and eventual death of the tree. American elms are the most susceptible. Siberian, Chinese and other elms are generally resistant but can harbour the disease.

To date, no trees in British Columbia have been found infected with the Dutch Elm Disease fungus.

The European elm bark beetle is present throughout southern B.C. Beetles have been found from Kamloops to Osoyoos and as far east as Trail, Nelson and Golden. A few have been found in Greater Vancouver. As one of the few areas in the world still free of DED, B.C. exports over 10,000 elm saplings annually. Only a few B.C. nurseries produce elm stock. A voluntary elm bark beetle management program is being followed by nurseries to prevent beetles from feeding and transmitting the disease to nursery plantings.

DED will also threaten landscape elm trees if it ever finds its way into B.C. But with early detection, the disease can be prevented from becoming established and spreading. Since other diseases and disorders of elms can look like DED, a positive identification by a laboratory is necessary to confirm it.

Anyone spotting elms showing the above symptoms is asked to contact their local Ministry of Agriculture and Lands or Ministry of Forests office, or send a sample of the affected branches directly to:

Brenda Callan
Pacific Forestry Centre
506 West Burnside Road
Victoria, B.C. V8Z 1M5.
(250) 363-0600

OR:

BCMAFF Plant Diagnostic Laboratory
1767 Angus Campbell Road,
Abbotsford, B.C. V3G 2M3.
(604) 556-3127

To ship samples, cut off several smaller branches with wilting or yellowing leaves, wrap them in dry or slightly damp newspaper, place in a plastic bag and a cardboard box and send by courier or express mail. Try not to let branches dry out too much before shipping, or become too wet - keep them in the refrigerator before shipping in hot weather. Please include information on the species of elm, age and location of the tree, when symptoms were first seen and your address and phone number.

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