Red Deer residents are being urged to hunt down a pest that’s taking a toll on spruce trees — especially young ones in new neighbourhoods.
The City of Red Deer reports that controlling the yellowheaded spruce sawfly during the next two weeks is crucial to stopping its spread.
The insect has been present in Red Deer for several years and populations continue to grow. It attacks Engelmann, white, black and blue spruce.
Elaine Johnson, urban forester for the city, said it’s especially bad in newer areas.
“The sawfly favours young trees, so neighbourhoods such as Inglewood, Kentwood, Johnstone Park and Johnstone Crossing are being hit particularly hard,” said Johnson. “The sawfly presence is also strong in Edgar Industrial Park. They are damaging trees throughout the city, but those areas are being affected the worst.”
The sawfly larvae are easy to spot. Adults are about 2.54 cm long and resemble small green caterpillars. Their heads are yellowish-brown and they have grey-green stripes running the length of their bodies.
They usually feed first on new foliage before moving onto older foliage. Damage may only appear on sections of the tree, but repeated attacks severely retard the height and radial growth of the tree and will eventually kill it.
The sawfly has one generation per year. It overwinters as larvae in soil-encrusted cocoons beneath trees.
Residents can pick the larvae by hand or prune the tips of branches where the larvae live.
Larvae and pruned tips should be disposed of in sealed garbage bags.
People can also use a high-pressure water spray to blast the larvae. Small larvae won’t be able to crawl back onto the tree, but adults may if they’re not removed after spraying.
“The yellowheaded spruce sawfly will continue to re-infect trees each year until the trees die,” said Johnson. “Our trees are a treasure that we can’t afford to lose, and dealing with the sawfly now is the only way to stop its spread to more Red Deer trees.”
Chemical controls can be found through the local garden centre or pest management companies. For more information on the sawfly and other pests, see www.reddeer.ca/parks or call Parks Department staff at 403-342-8344.