Homes infested by mice, rats, cockroaches and all type of creepy crawlies — Jacki Harkness has horror stories that could keep many homeowners up at night. As business owner in the pest control field and a member of the board of directors with the Structural Pest Management Association of Ontario, it’s her job to know all about household pests, as well as how to keep these unwanted invaders from destroying homes and becoming nightmares for their residents. Such pests can not only cause significant and costly damage but can pose a health hazard to humans.

What are some of the most common household pests?

• Carpenter ants. Harkness puts carpenter ants at the top of her list of common household pests in Canada. “If they get into your house, they are going to cause some structural damage,” she says. “They’re going to be chewing away two-by-fours between the walls, door frames, windows frames. As with all pests, it will only get worse if you don’t deal with them.” Carpenter ants come in different sizes (as large as 13 millimetres) but even the smaller ones are slightly bigger than the regular ant (as small as one millimetre). They’ll get under door sweeps, through hydro wires, and in little cracks in windows or door screens.
• Rodents. “Both rats [which are larger than mice and can weigh up to one pound] and mice [which have large ears, and are light brown to dark grey] spread disease, contaminate food and can cause structural damage,” says Dr. Mike Bentley, an entomologist with the Canadian Pest Management Association. “Unfortunately for us, our homes create the perfect environment for rats and mice to thrive. They can easily find their way into structures through gaps along poorly sealed doors and windows, or through poorly sealed holes where plumbing lines and electrical wires enter the structure.” Harkness adds that mice and rats can climb walls, with rats being especially potentially destructive and can create massive holes in structures.
• German cockroaches. There are many species of cockroaches, but this is a common one found in Canada, along with the Asian cockroach, which you’d find more in darker, more dank conditions, like a basement. The German cockroach, which is usually between 1.3 and 1.6 centimetres and is tan to light brown, is the more common one you will find in kitchens and bathrooms, Harkness says. They don’t usually cause damage, but can contaminate food and spread disease by walking over, and excreting on, food or food preparation areas. People with asthma can have a negative reaction to their droppings and body parts.
• Files. The colour and body size varies depending on the species, but they typically don’t get to more than 10 millimetres long. They can easily spread disease, since they move from rotting food, pet feces or disease-laden garbage to exposed food and utensils.
• Mosquitos. Anyone who has a cottage or camps knows full well about mosquitoes. They’ll grow in slow or still water and will bite and cause itchiness and irritation. In Canada, they can spread West Nile virus, which can cause flu-like symptoms or life-threatening illnesses and for which there is no vaccine.
• Bedbugs. These can be as long as 10 millimetres, with an oval, flat body that is brown or dark red in colour. They feed on the blood of people and animals while they sleep and can easily move from room to room. They prefer locations where they can hide, like areas where you sleep. Their bites can cause very itchy spots and some people can develop severe allergic reactions or secondary skin infections.
• Spiders. These are common, uninvited guests in Canadian homes with 99 species across the country. House spiders, which vary in colour from dirty white to black, and cellar spiders, which have longer legs, are the more common ones found in homes. Spiders don’t spread disease and only bite in defence but some people can have allergic reactions.

10 ways to deal with household pests

1. Seal up any cracks or holes around the perimeter of the house to prevent pests such as rodents and cockroaches from getting inside. And install screen doors and screens for the windows to keep out flies and mosquitoes.
2. Remove old landscape materials, yard waste and excess vegetation from the property to reduce potential harborage sites for rodents and ants.
3. Eliminate all moisture sources, including leaking pipes and clogged drains. Pay extra attention to kitchens and bathrooms, as these areas are particularly vulnerable to pest infestations.
4. Keep storage areas like attics, basements and crawl spaces well-organized and ventilated.
5. Remove or regularly change sources of standing water in your yard, such as bird baths, and address any poor irrigation issues that could create moisture issues on your property.
6. Dispose of garbage regularly and use trash cans with a sealed lid.
7. Clean food and drink spills right away and avoid letting dishes pile up in the sink so you don’t provide food for cockroaches and ants.
8. Carefully inspect the perimeter of the home for any signs of water-damaged wood or moisture issues that could attract ants and other insects.
9. If you suspect an infestation, always call a pest control professional.
10. If you are going to spray with pesticides purchased at a store, read the label so you’re using it properly, and that it’s the right product for the right pest. The Pest Control Products (PCP) number on the label will assure you it’s been approved by Health Canada.

Final advice from a pest expert

Harkness says she prefers not to use sprays while doing her job. “It’s invasive, first,” she says. “Spraying is just temporary. With roaches I feel like I am just pushing them further into the walls. I am killing the ones on contact but they’re mostly living in the walls.”

There are also natural ways to kill off pests like ants, spiders and mosquitoes using peppermint oil. But Harkness prefers aggressively “baiting” pests with chemical products that spread back to the source and wipe the infestation out more effectively.

“Bottom line, it all comes down to sanitation and sealing,” Harkness says.

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