Tiny Ants Around Your Home

As people are spending more time around their homes during the concerns of COVID-19, they may be more likely to notice small ants crawling in and around their houses. Now is the perfect time to do something about it.

There are approximately 200 species of ants in South Carolina. Most are native and most are good guys (or I should say good gals). However, there is one native species that can go from being benign to a pest when provoked by humans. This is the odorous house ant, Tapinoma sessile.

Odorous house ants feeding on liquid ant bait.

Odorous house ants feeding on liquid ant bait.
Photo credit: Michael Merchant, Texas Cooperative Extension, Bugwood.org

As their name suggests, odorous house ant is, well, odorous and can be comfortable living around your home. These 1/8-inch-long brown to black ants have been described as smelling like rotten-coconuts or suntan lotion when crushed. In natural settings, their nest size tends to be small with a single queen. For example, in a forest, an entire nest may be in a single acorn. In urban areas, nests tend to be very large with thousands or even millions of workers and many queens.

No one knows exactly why odorous house ants can explode in number in urban and suburban areas, but entomologist, Dr. Grzegorz Buczkowski from Purdue University has a theory. In a study, Dr. Buczkowski monitored odorous house ants in a forested area that was later cleared for a home. Before construction began, there were 20 species of ants on the site; after construction, there were 4 species with the odorous house ant the dominant group. The reason for the change was probably due to the loss of biodiversity. Many insects are adversely impacted by urbanization, but species like odorous house ants can thrive. Urbanization reduces competition for odorous house ants, and urban structures may increase potential nesting sites.

The spring is a good time to control odorous house ants (and similar ants) around your home before their colony numbers get huge and widespread in the summer. Check areas where these ants are traveling and where they may be entering your house. Look around windows, doors, and pipes. Remove food items on which the ants are feeding and keep remaining food in tightly sealed containers. Correct any moisture problems inside and outside the home. If you are home more, you may have a little extra time to fix those ripped window screens or caulk cracks the ants are using for entry.

Inside structures where the ants are entering and close to buildings, ant baits are usually the most effective control method. Place the baits to the closest point where the ants are entering the structure. Make sure the ants are feeding on the bait and that you use enough bait for very large colonies. You must give large colonies several weeks to take the bait back to the colony to kill additional workers and the queens. Sweet baits usually work best for odorous house ants, but not always. Sprays labeled for ant control containing insecticides can be sprayed outside structures in areas where the ants are nesting but do not disturb or spray the ants in the bait stations. Also, be careful not to overuse sprays as this can cause colony budding and increase the number of individual nests with their own queens.

If control is complicated or you get poor control on your own, consider employing a pest management professional. They have the equipment, products, and expertise for effective and safe ant control.

If this document didn’t answer your questions, please contact HGIC at hgic@clemson.edu or 1-888-656-9988.

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