Nelia Teves can't walk into her North York house without a handful of black and red cockroach-esque critters flying in behind her.

"Our entire neighbourhood is covered in them," Teves said.

She reached out to CBC News to find out what they are and whether she should be worried.

It turns out, they're more of an annoyance than a threat. They're called boxelder bugs and they're known as "nuisance pests."

Boxelder bugs live in Manitoba Maple trees, common in North York and Etobicoke. (Laura DaSilva/CBC) They don't bite, transmit disease or damage homes or plants. They're native to Southwestern Ontario and come out every year, but this year there was a baby boom.

Guelph University entomologist Morgan Jackson explained they lay their eggs and feed on Manitoba maple trees (or boxelder trees), which are plentiful in North York and Etobicoke.

The particularly dry summer made for prime breeding conditions. They love basking in the sun and congregate on south facing walls.

"They're basically like tiny little cats in search of sunlight to lounge and nap in," Jackson said.

In the late summer and fall they start moving away from the plants they feed on towards places where they can spend the winter safely.

"Nowadays, that usually means our homes," Jackson said. "They spend the winter as adults hiding in cracks and crevices. When the weather gets colder they'll go into hibernation."

A boon for pest control companies

Zafar Ahmad works for North York pest control company Pestend. He said throughout his long career, he's never seen this many boxelder bugs.

"In the last two days I've gone on ten calls. It's an epidemic. It's never-ending," Ahmad said.

Pest control technician Zafar Ahmad said the number of calls to spray for boxelder bugs this year has far exceeded previous ones. (Laura DaSilva/CBC ) Other companies also said their phones have been ringing off the hook about the critters.

Ahmad uses a chemical spray that kills the bugs within about half an hour and leaves a residue that lynches any that come along after.

Keeping bugs at bay without spray?

Toronto-based arborist and forester Stephen Smith said spraying the exterior of homes with water will drive them away for a while since they don't like cool temperatures.

He also recommends sealing windows and doors to prevent them from getting inside. If they do, he said there's not much to worry about.

"They'll leave a stain if you squish them, but that's about it."

He said people won`t be seeing much of the boxelder bug once first frost comes around.