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European Elm Scale Insecticide Treatments in Lethbridge

May 30, 2016 | 4:46 PM

LETHBRIDGE –  A small bug is creating a big problem for city workers in the parks department.

Lethbridge’s scale and maturity of elm trees is under attack from European Elm Scale.

The insect-born disease can hurt elm trees throughout its life cycle, causing branches to die and tree trunks to turn black in colour.

Six-hundred out of five-thousand trees across the city will be injected over the summer with insecticides to combat the epidemic.

Dave Ellis, Lethbridge Parks Manager, suggests that while the city will be taking action to save trees, the public should also monitor the health of their elms for signs and symptoms as trees can die off in just a few years.

“We have been working on the issue since 2006 and we’ve been busy trying to treat it ever since.”

Ellis said the city will treat the public trees with a costly insecticide, that while successful in killing the pests, the treatments typically must be repeated.

“We can do about 20 to 30 trees a day and will choose trees most valuable and most at risk.”

Want more information on Elm Scale in Lethbridge?

Author and renowned Horticulturalist Lyndon Penner will share insights on the “clear and present danger” threatening Lethbridge’s elm forest with the Upper Victoria Park Neighbourhood information session May 30th at 627 – 15th Street S. at 7 p.m.

How to Help Prevent the Elm Disease

– Water (even mature elm trees) regularly, especially during drought times
– Avoid damaging the root systems of the tree.
– Be aware of overhead branches and try not to break or damage any elm tree branches.
– Avoid compacting the soil around the roots of the tree (driving or parking vehicles on the roots) and opt for mulching the area around the tree.

Signs & Symptoms of European Elm Scale

– Visible mature insects 10 mm long, oval and greyish-brown with a white waxy fringe) on the branches or where the branches intersect the trunk
– Black sooty mold growth on the leaves, branches and trunk
– Late leaf growth in the spring
– Stunted, yellowing leaves leading to premature leaf drop and die back
– Honeydew secretions on leaves, branches or below tree.