Emerald ash borer: what Winnipeg tree owners should know

Winnipeg's first detection of emerald ash borer in 2017 changed the outlook for the city's ash trees. The beetle's larvae feed beneath the bark, damaging the tissue that moves water and nutrients through the tree. Infestations can become serious before a property owner notices much wrong.

The first useful step is to identify the ash trees on your property. Don't assume that every declining tree is an ash or that every ash problem is caused by this insect. Drought, root problems, and other pests can produce some similar signs.

An arborist can look for evidence of emerald ash borer and assess the tree's wider condition. Healthy trees and trees with minor infestations may be candidates for treatment. Trees with advanced decline or major defects may need a removal plan instead.

Watch for changes such as crown dieback, bark splitting, unusual shoots on the trunk, or increased woodpecker activity. Report a suspected infestation through the current local reporting channels, and get advice before moving ash material or firewood.

This post began as an early warning for Winnipeg tree owners. The dates and forecasts from those first years are no longer a substitute for current information. The provincial resource below explains the pest, while an assessment of your own tree can help you decide what to do next.