City of Saskatoon crews are inspecting trees in the Queen Elizabeth neighbourhood after confirming the first ever case of Dutch elm disease in the city.
"It can spread very easily," said Darren Crilly, director of parks for the city of Saskatoon.
The disease is caused by a fungus carried by the elm bark beetle. It interferes with the water conduction system, and has killed millions of American elm trees across North America, include many in Saskatchewan since it arrived in the province in the 1980s.
But Saskatoon has remained an island, free of the disease until now, because there are no natural elm stands along the river that can act as a corridor for the beetle.
Firewood suspected as source of disease
"We suspect that firewood is the main way that tree became infected," said Jeff Boone, pest management supervisor with the city.
But he noted they don't know for sure how the fungus spread. The city will not reveal the exact location of the infected tree, which crews started removing on Tuesday.
The response plan from the city includes inspecting other trees in the area for signs of the disease. If they find any others they will be removed and disposed of at the city landfill.
City workers will also examine trees in the surrounding area and a search for other sources of infection, and place five additional elm bark beetle adult pheromone traps in the area to monitor that insect.
"The parks division is following up and taking this situation very seriously," said Crilly. "We are following our response plan to minimize the chance of this disease spreading any further."
There is no indication that the fungus has been found in other parts of the city. American elms are one of the most common trees found along our streets, including the canopy of trees along Spadina Crescent.
Signs of Dutch elm disease include:
- drooping branches
- leaves that turn from yellow to brown
- tips dying back
- large portions of the crown that die
If you notice any of these signs you should notify the city's pest management department at 306-975-3300.
Preventing the spread of Dutch elm disease
There are several things people in Saskatoon can do to prevent the infection of trees.
- Not pruning elms during provincial pruning ban from April 1 to August 31
- Not storing or transporting any elm firewood. Provincial regulations already prohibit this.
- Dispose of all elm wood at the city landfill