Holiday decorating? Experts say to check for these invasive pests first

Invasive species experts are asking those decorating for the holidays to check their trees, wreaths and garland for hidden pests. 

Insect eggs from spongy moths and spotted lanternflies could be hiding under tree branches, while non-native plants like English holly, a staple plant in holiday arrangements, can pose risks to nature.

Experts say these invasive species have the potential to harm the local environment after decor is disposed of from people's homes.

"Invasive species don't rest," said Derissa Vincentini, the community science co-ordinator at the Invasive Species Centre. "You thought the growing season was over and you don't have to worry about them, but they could still be lurking in your holiday decor."

Christmas trees sold at big-box stores often come from other cities, Vincentini said, potentially bringing invasive egg masses along with them. 

While the egg masses, which can contain up to a thousand eggs, won't cause any harm in homes, Vincentini said problems arise when the insects get back outside.

"Once the spring comes and it starts to thaw, those eggs will start to hatch and then they can reach their hosts in the natural environment in a new location," she said.

Traditional holiday plants like English ivy, English holly and invasive barberry can also be harmful if they end up in London's natural environment, according to experts.

"Eventually they'll outcompete all of the native plants and really cause a lot of issues for the wildlife in urban wild spaces," said Janice Gilbert, the executive director of the Invasive Phragmites Control Centre. 

"Our native insects rely on our native plants for food sources, so if we're replacing our native plants with these invasive ones, we're reducing our insect population which reduces food for our birds," Gilbert said. 

Vincentini said spotting invasive insects in holiday plants is not always easy because the insects are not feeding on the greenery. 

"These egg masses are going to be very dormant so you're not likely to see any insects or any damage in regards to your Christmas tree," she said. 

"These pests are just very opportunistic when they're laying their eggs … especially if they can find a spot that's protected from the elements, so the underside of branches is a particularly good spot to look for these egg masses."

Spongy moth egg masses are about the size of a thumb and tan in colour with a felt-like texture, while spotted lanternfly egg masses look like a grey-brown smear of mud, she said.