Landscaper Paul Barker has worked on gardens throughout the GTA for 25 years.
In that time, the president of Newmarket-based Automatic Rain Landscape Irrigation has seen the dreaded box tree moth — an invasive species that can ruin the boxwood shrubs he helps irrigate — appear around Etobicoke and other parts of the GTA.
After getting a call from a homeowners in Aurora that his workers had not watered shrubs properly, he was disappointed to see the cause was actually the arrival of the nasty pests, which had ruined the shrubs.
Barker said this is the first time he has seen it creep into York Region.
“It’s inconvenient,” he said, adding that the pests will mean they have to tear out any shrubs impacted. “Then we will spray this every seven days for the rest of the year and then the next year. It’s inconvenient to the homeowner, too, because that’s more money for them.”
The company is warning its clients after discovering the pests this week. The invasive species is predominately in Ontario, spotted in Toronto in 2018. This year, the pest has spread to five other provinces, the first time it has been detected in Canada outside Ontario.
“It takes about three days to strip a hedge of its leaves,” he said. “It can be expensive.”
The Canadian Food Inspection Agency tracks the invasive species. Last fall, the agency detected them as far east as Windsor and as far south as Niagara.
The box tree moth is native to Asia. Larvae will feed on boxwood shrubs, including leaves and sometimes bark, resulting in disfiguration. The shrubs stand to lose colour and leaves, with the larvae leaving droppings at the base of the shrub.
“The defoliation and dieback are unsightly and reduce the value of the plants,” the Canadian Food Inspection Agency said on its website.
According to Landscape Ontario, control sprays safe for humans and pets can be used to kill the larvae when they are feeding. It also advises removing infested shrubs to control the species population. Infested shrubs and clippings should be removed, placed in a black garbage bag, enclosed tightly and placed in direct sunlight for 48 hours. That should kill larvae, and then you can add plant materials to yard waste bins.
“Moving forward, it is recommended that boxwood plants receive continual management to ensure box tree moth is controlled and to prevent further plant damage,” Landscape Ontario said. “Plants should be inspected during the general predicted larval periods for each generation of box tree moth.”
Generally, the insects will spawn three times in a year, with larvae emerging around May 15 to June 15, July 15 to Aug. 15 and Sept. 1 to 20.
James Lane of York Region natural heritage and forestry service said the region does not monitor this particular invasive insect.
Landscape Ontario advises that the periodic application of the chemical BTK can also be used to control the larvae.
Barker advises York Region residents to keep an eye out for them and do their research.
“I’m trying to prevent this, not just for my customers, but for everybody,” he said.
