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Better weather brings ant problem

May 2, 2019 GMT

Spring brings ant invasions. Beginning in spring, ants send out scout ants in search of food and water. Once found, they create a chemical trail to food and water for other ants to follow.

The most common home invading ant in Nebraska is the odorous house ant. The workers are dark brown or black and small, ranging in size from one-sixteenth to one-eighth of an inch.

They typically nest outdoors, but will nest inside. Outdoors, they construct nests in soil beneath objects like stones and patio blocks or debris. Indoors, they prefer areas with moisture such as under sinks or around hot water pipes.

Odorous house ants are strongly trailing ants. As they follow chemical trails to sweet food and water sources, they give new meaning to the saying “and the ants come marching in”. These ants forage even when temperatures are cool, as low as 50 degrees Fahrenheit.

Since the majority of ants nest outdoors, whether you find them inside the home or not; management includes reducing conditions conducive to nesting, locating and treating colonies, and using ant baits.


Many homeowners use outdoor foundation sprays. While these slow ants for a while, once the insecticide residue is gone ants often return.

Sealing or caulking openings ants may be using to enter the home is important to do; however, invading ants are quite small and we cannot make homes air tight.

For very short term relief, wipe the trail where ants are marching in a single file with a vinegar solution to interfere with the chemical trail. This will confuse ants but only for a very short time.

For longer term control, use sanitation and ant baits. Keep food residue off counters and eliminate crumbs in cupboards, drawers and on floors. Store food in airtight containers. Outdoors, avoid debris piles to reduce nesting sites for odorous house ants.

Ant baits are a good choice whether nests can or cannot be located and treated with an insecticide dust or drench. Toxic baits are taken by workers back to nests and fed to queens and other ants. If you are patient, baits can control an ant nest for the long term.

Place liquid ant baits or bait stations, such as Terro Liquid Ant Bait, Raid Ant Bait III or others, where ant trails are seen or where ants are foraging. Ideally, place these as close to where ants are entering the home as possible.

Once ant baits are placed, ants must be allowed to forage freely so they can take the toxicant back to the colony. When baits are used, do not use insecticides or foraging ants are killed before they can take the bait to the colony.

Ants often find baits quickly and within a day or two are foraging only the baits. It may take a few days to a few weeks before baits are effective and ants are no longer seen. Be patient.

Kelly Feehan is a community environment educator for Nebraska Extension-Platte County.