The City of Edmonton is keeping an eye out for what it calls a “deceptively attractive” and “tremendously damaging” invasive pest that has been spreading in Canada. The emerald ash borer is a bright metallic green beetle the city said has proven to be a “relentless killer” of ash trees in North America – with 99 per cent of trees in an infested area dying within 6 years of the beetle’s arrival. The insect, which is native to eastern Asia, lays its eggs in ash trees. The larvae then chew through the cambium layer of the bark and create tunnels that stop the flow of nutrients in damaged areas and eventually kill the tree. Mike Jenkins, senior scientist with the City of Edmonton, said the beetles were first found in North America in the 1990s.