Odorous House Ants don’t really stink up your house,  but they do smell like rotten coconut or citronella when crushed.  Often confused with Argentine ants, there is a difference in their bodies, but it can take a magnifying glass to tell the difference…..

Identification

Odorous house ants (Tapinoma Sessile) or “odorous ants” get their name because they have a rotten coconut odor when crushed. They are often confused with the Argentine ant and Pavement ant except that they have a single “flattened”  node hidden under their abdomen. It is not visible from above or the side because it is almost completely hidden.  In comparison. the Argentine ants node is pointed and very noticeable.

Odorous house ants are small, brownish ants about 1/8-inch (3 mm) in length. Their workers are all the same size.  A single colony may contain several queens (polymorphic) and around 100,000 workers.

They are also closely related to the ghost ant but are easily distinguished by size and coloration.

Ghost ants are considerably smaller and have a dark head and thorax, and a pale almost translucent abdomen and legs. The antennae of both ant species have 12 segments and no club.

Odorous house ants rival Argentine and crazy ants in their persistence in invading buildings.  Its basic biology and habits are similar to those of the Argentine ant.  For this reason, these ants are often confused.  One identification fact is that Odorous house ants tend to be smaller and the workers are all the same size.

Where They Are Found

Odorous house ants are found throughout the United States and from Canada to Mexico. It is a major structural pest in California, particularly in central and Northern California. Its presence in Southern California is less in areas populated by Argentine ants.  For some reason, Odorous house ants don’t like areas where Argentine ants exist.  This makes their proper identification that much more important.  In areas where Argentine ants are known to thrive, you could be dealing with Odorous house ants.

Odorous house ants are also found along the pacific coast into Oregon and Washington. In the mid-south regions of the U.S. such as northern Mississippi, west Tennessee, and Arkansas, it is the primary pest ant invading buildings.  They also can occasionally be found infesting structures throughout the lower Midwest valley.

Tramp Ants

Odorous house ants are considered a “tramp ant” due to their ability to infest buildings and become a major nuisance.  Those ants that are considered Tramp ants are a problem in many countries around the World and in some cases inflict moderate economic damage.

As seen with many successful “tramp” pest ants, Odorous house ants have multiple queen colonies numbering tens of thousands of workers. Huge extended colonies, or “super-colonies of foraging trails along which workers, food, and brood (larvae and pupae) are exchanged. The workers from separate colonies are antagonistic to each other so separate colonies will not integrate and split apart as is seen with the Argentine ant. Workers and queens may live for several years.

Colonies also frequently form under the loose bark and in cavities of trees, in bird and animal nests and in honey bee hives. The colonies locate themselves in the top of the hives, apparently for the warmth the hive produces. The ants feed little on the honey even though they are ravenous sweet eaters.

Food Sources

Odorous house ants prefer sweet and sugary foods.  Aphids, mealy bugs and the honeydew secreted by them are their favorite food source.  For this reason, sugary based based baits such Greenway / Gourmet Liquid Ant Bait work well to control them.  Granular baits won’t work since the worker ants don’t eat solid foods.  Odorous house ants also feed on plants, plant juices and many different insects.

How To Get Rid of Odorous House Ants

Spraying liquid pesticides for Odorous house ants usually will result in rapid egg laying.  This causes them to multiply faster making them worse.  In order to kill and control these ants, the nest and the queens have to be eradicated and egg laying stopped.  Spraying chemicals on baseboards and in cabinets won’t kill the queens or hidden nest(s) inside the walls.  Spraying outdoor areas can be expensive, time consuming and require repeated frequent applications.  In most cases, using a liquid ant bait to control them works best.  But it has to be applied outdoors.

Indoor Control

Indoors, Odorous house ants commonly nest in wall voids in insulation.  They prefer to nest near and close to heat sources such as hot water heaters and hot water pipes.  They have also been known to nest under bathtubs, in the walls of shower stalls and on exterior walls.  Odorous house ants particularly prefer walls that are facing south and west. These walls will absorb more sunlight and heat in the afternoon making them vulnerable to infestation.

Insecticidal Dusts

Dusting of walls and voids with an insecticidal dust such as BorActin Dust will help provide control and kill Odorous house ant nests.  Removing wall switch plate covers, plumbing access points (rings around faucets, drains etc.) and making small holes directly through sheetrock is usually necessary to apply the dust.  Worker Odorous house ants will crawl through the dust and die.

In most cases a slow acting dust such as BorActin (boric acid) is best because it doesn’t kill the ants instantly.  Instead, it’s a slow kill giving them time to go back to the nest where they die.  In time, the entire colony will slowly starve from the loss of the worker ants.

When dusting, use a small hand duster such as the Puffer Duster.  The dust needs to be a very thin film, such as dust on a TV or furniture.   Any thicker dust layer and the ants will crawl around it.  Using a spoon or applying directly out of a bottle won’t work as it leaves clumps.  Don’t apply dust to baseboards or cabinets.  It is only applied inside of hidden areas such as walls, or in cracks, crevices, etc. If you can see the dust, it is not applied correctly.

Gel Baits and Bait Stations

Odorous house ants can also be controlled by using Ant Gel Baits such as Advion Ant Gel Bait – if they feed on it.  This bait has to be applied wherever the ants are seen.  It also have to be monitored and replaced as soon as the ants devour it.  Daily inspection of the bait is necessary and re-baiting until the ants are completely gone is essential.  Putting out a gel bait one time will not work in most cases.

Bait disks such as  Maxforce Ant Bait Stations are a professional quality product that are easy to use and can also kill Odorous house ants.  Simply place them wherever ants are seen and replace them when the bait is gone.  This station has red see through lid that allows you to see the bait.  When the bait is devoured by the ants, replace the station.  Keep replacing the stations until all signs of ants are gone.

If insecticidal dusts,  gel baits or bait disks don’t seem to be working, then focus your efforts outdoors.  Outdoor control of Odorous house ants is key to long term control.  Any indoor control can be short term.  If they are nesting and colonizing outdoors, then an outdoor treatment program is essential to any control effort.

The KM Ant Pro Liquid Bait system is the best overall approach to Odorous house ant control and is only used outdoors.

Outdoor Control

Outdoors, Odorous house ants live under mulch, bark, rocks, logs and almost anywhere a damp environment exists. Treatment of these areas with a residual liquid insecticide can help and even eliminate them entirely.  These ants can also live in trees and shrubs due to their affinity for aphids and mealy bugs which produce honeydew –  a sugary substance that Odorous house ants love and routinely feed on.

The problem is that an complete treatment of the lawn, trees and shrubs and every possible location where they live can be difficult.

One gallon of liquid pesticide per 1,000 square feet is the normal rate of application. If the lawn or area around the structure is several thousand square feet, it will take many gallons of spray with a hand pump sprayer.  A quarter acre lawn (12,000 square feet) will take 12 + gallons of spray not including trees and shrubs. If on the other hand commercial spraying equipment is available, then this type of treatment may be more realistic.

The best liquid insecticides to use outdoors are Talstar, Bifenthrin, Demand CS and Onslaught Fastcap.   These products vary in price with Bifenthrin being the least expensive and Onslaught Fastcap being the most expensive per gallon of mix.  Onslaught Fastcap is microencapsulated and will last up to 6 weeks outdoors.

Outdoor Baiting

Outdoor baiting with liquid baits is the best overall approach to eradicating Odorous house ants.  The only product that works is the KM Ant Pro Liquid Bait Dispenser with Greenway / Gourmet Liquid Ant Bait.  This patented dispenser dispenses liquid baits over months and months without any need for maintenance.  Simply replace the bait every 90 days for best results.

When Odorous house ants find the KM Ant Pro dispenser, they begin feeding.  The active ingredient used in Greenway / Gourmet Liquid Ant Bait is boric acid – the same material mentioned earlier in BorActin.  The ants slowly begin dying and over a period of 60-90 days. The nests and colonies soon starve and crash.

The benefit to using outdoor liquid baits, is that the workload and treatment time is reduced drastically.  There also is practically ZERO effect on the environment because no pesticides are used.  The main benefit however is that ants located off premises can be intercepted and killed before they infest and start new nests.   Outdoor baiting can provide a barrier to help prevent future infestations.

The KM Ant Pro Liquid Bait System not only kills Odorous house ants indoors, it kills them outdoors.  That’s because ants the infest indoors will go outdoors to find food sources.  The KM Ant Pro System provides this alternative food source.  It’s proven in University testing by the University of California at Riverside and has patents in the USA and in Europe.  If you are looking of an easy solution to killing Odorous house ants, there really is nothing easier than the KM Ant Pro System.

RELATED ARTICLE:  KM Ant Pro Liquid Bait System

If You Must Spray Pesticides…..

Spraying will kill the exposed worker ants, but it will not kill the entire colony.   If you are going to spray, make certain you know exactly what you are spraying and that it’s  a “non-repellent” insecticide.  Non-repellent means the insects cannot detect its presence and will trail over it unknowingly.  They pick it on their feet and antennae by crawling over it causing death.

Non-repellent pesticides are not available at hardware stores or most farm and feed stores. Almost all are professional quality and only available through a specialty distributor such as ePestSupply.

Phantom Insecticide is an odorless, non-repelling pesticide that kills ants within a few weeks of application. Phantom works by entering the ants nervous system through grooming and food sharing and then systematically kills the ants through a degeneration process. Phantom is a “metabolic inhibitor” and kills ants very slowly.   It can be effective at controlling most hard to kill species of ants.  It is also labeled and used for termites, cockroaches, and others.

Fuse Insecticide and Termidor Foam can also be used. These products can kill Odorous house ants, but are not as efficient as liquid baits.  They are also considered moderately toxic making them unsuitable for use in sensitive areas such as hospitals and nurseries.

Insecticide dusts such as Timbor and BorActin can be used inside of walls, voids and cracks and crevices. These products are essentially Boric Acid based, non-repellent and very safe.  Insecticide dusts will not kill the colony and will only kill the exposed worker ants.

Make It Easy

There are many products available to kill Odorous house ants.  There are also many different opinions on how to control them. The bottom line is that the nests have to be controlled in order to stop the egg laying and breeding cycles.  Whatever method you determine is best for your needs, be sure to take into consideration the amount of time and potential frustration by using a “cheap” or inexpensive hardware store variety spray or bait.  These products simply do not work and are not the same as commercially available products.

Outdoor baiting with liquid baits such as KM Ant Pro Bait Dispenser with Greenway / Gourmet Liquid Ant Bait is a long term solution to getting rid of Odorous house ants.  It will provide them with food sources outdoors and help prevent migration indoors. This system also helps intercept outside invading ants and creates a barrier to help prevent re-infestation outdoors.  Year round use of this system can aid greatly in getting rid of ants and preventing infestations.