Stop dutch elm disease – don’t prune

A pruning ban has gone into effect to protect elm trees.

Elm trees, which are very popular in the city and on farms and other places in the country are susceptible to Dutch Elm Disease, a fungus that is spread by a tiny beetle.

STOPDED, a provincial organization working to stop dutch elm disease, the city of Lethbridge and other groups are telling people not to prune elm trees from now until September 30th.

Dutch Elm Disease spreads rapidly and destroys elm trees quickly. It can take out entire stands of elm. DED is not in Alberta yet and strong efforts are being made to keep it at bay.

“A lot of people are watching for this just to keep it out of Alberta,” said Lindsay Bell, a city of Lethbridge arborist. “We’ve got one of the most significant stands of elm trees left in the world.”

Dutch elm disease is transmitted by elm bark beetles.

STOPDED executive director Janet Feddes-Calpas said, “If elm trees are pruned during the pruning ban period, these beetles which are active at this time can be attracted to the scent of the fresh wound and possibly infect an otherwise healthy elm with DED. Once an elm tree is infected with DED it will die within a year.”

The city, STOPDED and others are asking people to watch for symptoms of dutch elm disease.

“If all the trees in you neighbourhood are leafing out and your elm tree hasn’t leafed out definitely give us a call and we’ll come and take a look,” said Bell. “Once we get into the warmer months of summer what we’re asking people is to just watch. If you see your tree wilting all of a sudden, you see some significant wilting going on and then those leaves usually curl up and remain on the tree. Something like that is something else that we would like to come out and take a look at that tree.”

People are also being told not store elm wood. Instead, take it to the landfill and dispose of it because beetles are attracted to stored elm. People are also being advised not to bring elm wood, or firewood of any sort into the province or the city.

Sticky pheromone traps are used to monitor where various insects are and to determine whether certain ones are in the area.
So far, efforts to keep dutch elm disease out of Alberta are working.

“Last year we found zero elm bark beetles in Lethbridge,” said Bell. “That was a good sign. One year I believe we found 52.

Officials hope they don’t find any elm bark beetles in this year’s traps.