Ants in your house or yard: July 2010 Archives

Help! I have ants in my kitchen and want them out! How do I get rid of the ants in my house?

- Oscar, Oakland, CA, USA

Thanks for contacting us at AntBlog!

Although many ants are quite beautiful and really have no interest in entering our homes, there are a few species that we call "household pests". Depending on where you live resources to identify the particular ant species you have invading your home may or may not be possible, but knowing which species you are after can help. A helpful resource to identify common household pest ants can be found here.

There are several ways to try to control or exterminate these unwelcome ant guests in your kitchen or other parts of your home:

1) Clean. If you know where the ants are coming into your home, you could try to discourage them from coming in. This can be done several ways including making sure their food sources are unavailable (store foods in airtight containers). Also it is important to keep any areas where you see the ants foraging or coming in very clean which includes wiping down any areas with soapy water. This is not because the ants are dirty, but because they communicate with each other by laying scent trails (pheromones) where they walk to let others know where to search for food.

2) Discourage. Another option would be to block/exclude them from coming into your home. There are many products available for this at your local hardware store such as caulk or petroleum jelly, but you could also try using a very fine, silty powder (such as cinnamon, cayenne pepper, diatomaceous earth, corn starch, etc.) to plug any holes the ants are using to come into your home. It will be most effective if you can figure out where they are coming into your home on the inside and outside and block both entrances. You will have to keep reapplying until you no longer see any ants in your home. The fine, silty powders get stuck in the small hairs on their legs and body and since the ants do not seem to like this they avoid these areas. These are also good options if you would prefer not to use chemicals or if you have small children or pets around. This will not kill the ants, but simply discourage them from entering your home.

3) Toxic baits. If the above methods are not effective, then you may have to move onto using toxic baits. In most cases sweet sugar baits such as Boric acid (use low concentrations with less than 1% of the active ingredient) will be effective. Using indoor sprays are not effective. Although these sprays will kill the individual ant you see foraging in your home, the nest and queen are still nearby and will keep producing ant workers which will find their way into your home. This is why you need to use a toxic bait, which kill the ants slowly so the ant worker will take the poison back to the nest and will eventually get to the queen and kill the entire colony. You will want to place the baits in areas where you see the ants foraging or coming into your home and be sure to place them away from areas where children or pets are likely to find them.

Although most ants we find in our homes are only searching for food or shelter and are really only eyesores and do not really cause much real damage, there are one group of ants that can cause structural damage to your home. These are carpenter ants. Identification and treatment of carpenter ants is essential with these species. These ants do not eat wood, but burrow through wood to build their homes. So as their colonies get larger they need to bore through more wood to make larger cavities, which can damage any of the wooden parts of your home such as windows, doors, internal beams, or subfloors.

If you are finding winged ants in your home, you may want to read this AntBlog post:

Although ants in our homes can be a nuisance, remember that most ants are actually quite beneficial for the outside environment and local ecosystems. You can read more about the benefits of ants here:

Good luck!
Corrie Moreau & the AntAsk Team


I'm trying to decide whether to exterminate the ants living in grass/twig/leaf mounds around my property. If they are not native I intend to try to eliminate them.
I live about 30 minutes outside of Portland, Oregon at about 1500ft elevation. My land is mostly wooded but with grassy, sunny areas with orchards trees and garden areas. Over several acres there are at least 6 ant mounds each 6-24" tall and 12-24" across in the grass or at the edges of the woods.

The ants have red heads and near black bodies. They are about 1/4" long (not less than that but not close to 1/2"). From looking over some ID keys online here's what I know to look for that describes these ants:

Petiole with 1 node and is very distinct (spiky)
Thorax is uneven
Head is red and thorax and abdomen are black or very dark brown
Antennal clubs are indistinct (or absent)
Eyes are black
No stinger is visible
Seem to be two (maybe three) black dots between the eyes and much smaller than the eyes.

If there's a good resources that you can point me toward to do my own research that would be great too.

I hope that you might be able to help.

Thanks much,
Joshua (Portland, Oregon, USA)

Dear Joshua,

Thank you for the very detailed and helpful description of the ants you are finding on your property. This really helps to narrow down the ants you are likely finding. From your notes on the ants themselves and their mounds it sounds like you likely have Formica (wood ants). You can see images of many of the species here and here.

These are likely native species and although their nests can be unsightly on a well-manicured lawn they are no threat to you, your children or pets, or home. The species you are finding probably belongs to the "Rufa group".

To identify ants you find on your property in the future, I would recommend "Ants of North America: A Guide to the Genera" by Brian L. Fisher and Stefan P. Cover.

Thanks for contacting us and keep enjoying your native ant fauna,
Corrie Moreau & the AntAsk Team

Dear ant experts,
I found these large ants yesterday in my backyard. I have never seen them before.

No one I know has been able to identify them.
I was hoping you could identify them and tell me a little about them.
Through observation these are some details I can tell you about them.

Their color appeared to be a pearlescent orange red color in sunlight.
They were about an inch in length.
The appeared to be rather thick for an ant.
Some were winged and others not winged.
I tried to capture one and they were quick and evasive.
I live in Palmdale, California which is located in Mojave desert, high desert area.

I have uploaded the pictures on photobucket. Here are the links:

Thank you in advance,
Palmdale, California

Dear Efren,

Thank you for contacting AntAsk and including photos of your mystery ants! Not only do the photos really help us with identifications, but also knowing where you live really helps us narrow the list of possible ant species.

From the photos and description you sent of the ants you are finding in your backyard, it looks to me like you are seeing species of harvester ants from the genus Pogonomyrmex. Although it is difficult to tell exactly which species you are observing, it seems you are likely finding either P. californicus or P. rugosus, but you can see a list of all the species of Pogonomyrmex found in California on AntWeb here.

You can also see additional photos of each Pogonomyrmex species and distribution maps here.

Pogonomyrmex ants are called "harvester" ants because they collect seeds to feed on (called granivory). You can often find them carrying seeds back to their nests and ant photographer, Alex Wild, has some great photos of this behavior on his website here.

You mentioned that you saw both winged and non-winged individuals. The winged ants are the female and male sexuals getting ready to go on their nuptial mating flight. You can read more about this on a previous AntBlog post here.

On a last note, I should mention that harvester ants are often known for their painful stings, so be careful when trying to collect them. Remember that ants, like most animals, usually only hurt humans when they feel threatened. So as long as you are not trying to pick them up or dig into their nest, you are not likely to be stung. Enjoy their beauty and remember that they are part of the native habitat and serve many useful services in the ecosystem (including dispersing seeds).

Thanks for sharing your ant photos!
Corrie Moreau & the AntAsk Team

Hi there,

I live in Brisbane in Australia, and recently a species of ant has been snooping around a pot plant in my first floor apartment.

I haven't been able to figure out what sort of ant it is, but I'd be interested in finding out.  I also have house ants sneaking in the same area (which I'm trying to discourage as they bring in aphids) and the two species seem to get along just fine.

I've attached a few pictures to help with identification.

Many thanks,
Brisbane, Australia

Dear Caroline,

Thank you for contacting AntAsk and sending photos regarding the ants you have in your apartment in Brisbane, Australia.  There are actually quite a few helpful resources for identifying ants in your region.  I will include some links below, but I think the resource that would be most helpful is a small pocket guide book "Ants of Brisbane" available at the Queensland Museum in Brisbane (and likely in other bookstores):

It appears to me that the ants you are finding in your plants belong to the genus Polyrhachis, sometimes called "spiny ants":

These ants do not sting and are rarely aggressive.  As they can tend plant feeding insects for honeydew, this is likely the reason you are finding them on your houseplants. Here are some more useful links to ants in Australia (sometimes these links need to be reloaded several times to work, so be patient):

If you know where the ants are coming into your home, you could try to discourage them from coming in.  This can be done several ways including making sure their food sources are unavailable. In this case you will need to make sure you get rid of all plant feeding insects such as aphids, scale insects, etc. Another option would be to block them from coming into your home. There are many products available for this at your local hardware store, but you could also try using a very fine, silty powder (such as cinnamon, cayenne pepper, diatomaceous earth, corn starch, etc.) to plug any holes the ants are using to come into your home.

Thanks again for sending photos of your beautiful ants!

Corrie Moreau & the AntAsk Team

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