Fredericton plans to increase efforts to combat Dutch elm disease

Fredericton is doubling its efforts to protect its trees againstDutch elm disease, a tree-killing fungus.

The disease spreads from elm bark beetles feedingunder the bark of the tree during winter.

Last year, the city inoculated 124 trees with a vaccine called DutchTrig, a biological and organic control agent.

Itplans to double that number this year, said city arborist Keanen Jewett. The city plans a "proactive" treatment-basedapproachrather than removing infected trees.

"It's what we feel is probably the best and only control we have other than [removing trees]," Jewett said.

Dutch elm disease can cause a tree's branches to wiltand its leavesto turn yellow in the middle of the summer.

The citycut down severalelm trees last year to prevent the disease from spreading.Jewett said more could be cut this year, if necessary, but inoculating trees is cheaper than removing them, according to a news release from the city.

The DutchTrig vaccination is designed to protect trees from becoming infected with the disease. It isn't able to cure infected trees.

"At one time, we had a huge population of elm trees, well over 7,000 estimated in the city,"Jewett said. "We're down to about 1,000. Our hope is to save the elms."

The city doesn't surveytrees for Dutch elm disease until around mid-July, Jewett said, so it won't know how many are infected until then.

Trees inoculated last year will have to be treated again becausetrees grow an outer layer each year that's subject to infection, Jewett said.

The DutchTrig vaccine is only being used on trees that grow on city property.For trees on private property, Jewettsaid the city plans to advise residentsto use DutchTrig ontheir trees as well.

But the cost isn't covered by the city, which means homeowners will have to pay for the vaccine. Jewett estimates the cost of inoculating one tree is up to $150.

"If we did come up with a program that maybe we could encourage people to piggyback on, then we'd maybe have the hopes of reducing the costs a little bit to make it more feasible for people."