John Maher: Hi, I’m John Maher and today I’m here with Tim Chase of Colonial Pest Control. Tim is an entomologist and a pest control technician and today our topic is how do mosquitoes get into my house? Welcome Time.

Tim: Good morning John.

Ways Mosquitoes Can Get Into a Home

John: So Tim, what are some of the ways that mosquitoes can enter my house?

Tim: Well, there’s a variety of ways that mosquitoes can enter a structure. One of the main ways would be through open doors and windows. [For example] an attic with screening, holes in screens, leaving doors open, and in some cases, kids will leave the slider and mosquitoes have easy access at that point. Mosquitoes also seek shelter from wind and conditions that are unfavorable and may fly into the garage to seek shelter and shade. They may get trapped inside the house. Or, as you come into the house, the mosquito simply flies through the door with you.

John: Right. How small a space can a mosquito get through? You mentioned screens and I know that sometimes your screens get a little damaged and you might get a tiny little hole in it. Is that big enough for a mosquito to get through?

Tim: Well, mosquitoes are extremely small insects. They’re not actively seeking out holes in your screens, but as they stand on the outside of the screen looking in, they may be attracted by carbon dioxide heat, some of the light inside the house. Some species are attracted to light. So they may be walking along the screen and sort of just encounter an opening. I know in my son’s room, there’s a screen patch that [covers] about a 2×2” hole, and I always wonder if that falls off, if a mosquito could get into his room. It’s certainly possible.

During What Seasons Are Mosquitoes the Most Common?

John: Are there particular seasons when mosquitoes are common?

Well, mosquito species and their activity really depends on the season and conditions. There are species that are present in the early spring, summer, and the late summer. The earliest species that arrive are really sort of few and far between. There’s not a million mosquitoes. As the season progresses though, some of these species have multiple generations, so you can actually get many, many mosquitoes. As we get into the late summer to early fall, the mosquito population seems to be a little bit higher. That’s when you’re more likely to get a number of mosquitoes in the house.

Pets Bringing in Mosquitoes

John: Right. If I have pets, can will they bring [mosquitoes] in as well?

Tim: Sure. If your dog has been laying outside and he’s got mosquitoes feeding on him, it usually takes a little while to feed on the pet. If they’re actively feeding and the pet walks in the house, they may actually transfer a loaded mosquito filled with blood. Sometimes you find those big mosquitoes on the wall that are just engorged with blood, that have just had a blood meal. They’re probably not going to make it out to the water source at that point. Depending on the species though, if it’s an indoor breeding species, they could lay their egg mass inside a potted plant, or some type of water source within the structure. So that could be an issue for mosquitoes living in the house.

Places in a Home That Are Attractive to Mosquitoes

John: So it could potentially be even be breeding mosquitoes right in the house.

Tim: Absolutely. If you’ve got potted plants, or things like maybe an unused waterfall within the structure or things like that. Water features, koi ponds, etc. There’s a lot of different things that people have in their houses that could contain standing water, and that’s certainly an adequate spot for some of these mosquitoes.

John: Of course, if I’m not maintaining my house properly and I have little leaks or something like that, leaks can create standing water, maybe inside the walls or something.

Tim: Not so much inside the walls, but if you had a five gallon bucket of water under a leak. So that’s sitting in the basement, so that could be something that would be attractive to mosquitoes. I had a woman that was rooting plants, so there were little containers of water with starting plants and we did find mosquito larvae right in there. It’s very interesting to see the mosquito larvae. It’s a little curled up guy, and when disturbed, it inches down into the water to get away from any predators. But it’s got to actually swim up to the surface and breathe at the surface of the water.

If you find a pot or something and you approach it and you give it a little tap, you’ll see the little mosquito larvae head down into the bottom of the pot. You can actually see these guys.

John: And then you know you’ve got mosquitoes breeding there.

Tim: And it may be as simple as changing the water more frequently in your plants and trying to eliminate access points for the mosquitoes that would want to breed inside.

What Attracts Mosquitoes?

John: What are some of the things that attract mosquitoes? You mentioned some are attracted to light, some are attracted to the carbon dioxide that we breathe out. Is there anything else that can attract mosquitoes?

Tim: When you think of a structure of a house, there are many different conditions around them. You can take two houses that are different and compare them. A house that is completely shaded with canopy and has heavy shrubs around the house, those are going to be ideal resting spots for mosquitoes to be waiting for a host or waiting for their more active time to feed. So when the mosquitoes aren’t feeding, they’re actually resting in these places so they don’t dry out. Compare that to a house that has very little shrubbery, there are no trees over it, it’s very light and has a little more air flow around the house. That house is probably going to have less mosquitoes just around it generally. If I was to pick one of the two that would have more mosquitoes getting inside, it would probably be that house in the shady area, just for the increased amount of mosquitoes there.

Other factors could include the [house’s] location to a salt marsh or a stagnant body of water. Let’s say your neighbor isn’t using their swimming pool. A swimming pool can have millions of mosquitoes who are going to emerge and seek a host. So if the conditions are right in your area, you’re going to have more mosquitoes than someone who is say maybe living out in an open field area. They’re still going to have some mosquitoes. I know that on the sea coast area, there are those salt marsh mosquitoes and in the fall and late summer, there can be massive populations of these things and they’re really aggressive when looking for a host.

John: Right.

Tim: As you’re walking into the house, mosquitoes are following you in the air. They can actually be drafted into your structure or are sitting on you while you walk in. Then, this big mosquito will actually hunt you down in your house. It’s pretty relentless. You know, you go to swat it and it hides, but a few minutes later it’s back.

John: Right, right. It seems like when you swat at those things, they never seem to actually go away. They go away for a minute and then they come back and they bother you.

Tim: The air flow from your hand pushes them out of the way.

John: Then as soon as that air flow comes down and they’re back again.

Tim: An interesting trick inside the home if you’ve got a sitting mosquito is Windex or a cleaning solution. A good shot on them will pretty much drop.

John: Just a little spray.

Tim: Then you can clean up the wall too, right?

John: While you’re at it, clean the windows.

Tim: Right. Most of those home cleaning solutions are pretty good at killing the little insect as long as you’re not allergic to it or it doesn’t stain the surface.

How to Reduce Mosquitoes In and Around the Home

John: What are some of the things you can do as a homeowner to make mosquitoes less prevalent around your house? Obviously, there’s not going to be much you can do if you do live right next to the salt marsh. You’re not going to be able to get rid of the salt marsh, but you might be able to trim back some of the bushes and shrubs and things like that.

Tim: Sure. There are a whole list of things that can be done to minimize or mitigate some of the mosquitoes. No matter where you go, mosquitoes are really good fliers. So there’s always the potential a mosquito is going to fly your way. [Try] reducing shady areas, leafy shrubbery, and keep the edges of the yard as clear and light as possible, maybe move play areas farther from the edge of the forest or the yard where the mosquitoes are harboring. Keep low bushes and stuff away from the property and create airy areas. Remove breeding sites such as standing water. Just anything can be a breeding site, you’ve got bird baths, a can sitting under the deck, a five gallon bucket can have thousands and thousands of mosquitoes in it. Old kiddie pools that aren’t being used, above ground pools and in ground pools that aren’t being used, canoes sitting under the deck, and old tires are one of the famous ones.

John: Oh yeah.

Tim: It just holds that water in there. People are saving the tires for something, we don’t know what. They’re just under there holding water. No matter how you put a tire, it’s got a place that can hold water. Old, unused potting equipment, wheelbarrows, just name anything that can hold water.

John: So it’s probably a good idea to walk around your house and your yard and just look for any place where there might be standing water. Especially maybe after it rains, walk around and just take a look and see, “Oh, wow, there’s a bucket of water there. What about that old tire I had under my deck?”

Tim: It might be as quick as tipping it over, but some of these mosquitoes only need 30 days to 4 weeks of standing water and they can do a whole generation right there. It’s really incredible how fast a population can develop. I do a lot of exterior work, and I’m forever dumping bird baths out, tipping canoes over, letting water out of tarps, you’ll see as the tarp is just sitting there.

John: It’s all crumpled up and there’s lots of places where there’s water.

Tim:  And every little pool has 1,000 mosquitoes in it and I’m getting bitten while I’m going around the house.

John: Wow.

Tim: Also, you’ll see sometimes, depending on which way the wind is blowing and how many mosquitoes there are, it’s interesting how the mosquitoes will get out of the wind by going to the lee side of the house. So sometimes, you can go around the back of the house and there will be thousands of mosquitoes just resting out of the wind. So that might be a spot where if you open the back door, some of these guys might come right in the house. It’s hard to prevent that.

John: Right.

Tim: Another way to prevent mosquito activity might be an exterior treatment. Professionals are doing treatments. These treatments are generally safe and effective. They don’t contain and control every single mosquito on the property, but if done properly, it can drastically reduce the population of mosquitoes at a given location.

John: Right, you spray into the woods around the area and around the outside of the yard, things like that.

Tim: What the treatment is designed to do is to contact the insects as they’re going to their normal resting spots. So that would include leafy foliage, shrubs and plants near the house, with the exception of flowering plants that have honeybees on them. Anything that is producing crops, we don’t spray gardens or things that bear herbs. Even non-edible fruit trees could be considered a crop in some cases.

We try to really focus on the areas that are going to be effective, where the mosquitoes are going to rest. That’s been established to be a useful tool in reducing mosquito populations. It’s more of a management tool that goes right along with everything else like removing the water sources, checking your screens, using insect repellent, avoiding times when mosquitoes are really active, so there’s a lot that can be done to minimize mosquitoes in your home.

John: Alright, well that’s really great information, thanks for speaking with me today Tim.

Tim: Thank you very much John.

John: And for more information, you can visit the Colonial Pest Control website at colonialpest.com or call 1-800-525-8084.

Photo Credit : By James Gathany | Centers for Disease Control and Prevention‘s Public Health Image Library