Ant Control: Why the Ants Come Back After You Spray Them

You find a line of ants on the kitchen counter, grab the can from under the sink and spray it. The line is gone by supper. A few days later there are ants at the bathroom sink, and a second line along the baseboard in the dining room. The spray did what the label said it would. It also made the job harder.

Here is why ants come back after you spray them, where they are coming from in the first place, and what ant control looks like when it goes after the colony instead of the trail.

Why do-it-yourself ant control makes the problem worse

Most ant sprays on the store shelf are contact killers. They kill the ants they touch and leave behind a residue that repels the rest. That sounds like what you want. It is not. The ants you see on the counter are the foragers. The colony is somewhere else, and it is still very much alive.

When the trail runs into that repellent residue, the ants do not give up. They divert around it and find another way, and the colony can split and spread to new parts of the house. When we are called to a home where somebody has already treated, we often find piles of dead ants where the spray landed and colonies that are still active throughout the house.

The store products are also usually about half strength, with little lasting effect. By the time you have bought several of them and put the time into using them, you have typically spent more than a professional treatment would have cost from the start. We wrote more about that in our guide to do-it-yourself ant control.

Where the ants come from: aphids, honeydew and the flower bed

The ants on your counter started outside. In the spring and summer their natural food is honeydew, a clear, sweet liquid given off by aphids, the small insects that gather on flowering plants. Ants like it so much that they farm the aphids for it. They herd them and protect them from predators, much the way we keep livestock.

That is a chain we see over and over. A lot of flowering plants around a house attracts aphids, and the aphids bring more ant activity. Southwestern Virginia has plenty of native flowering plants, and many of us add flower beds on top of that. The aphids enjoy a flower garden as much as the gardener does.

It is also why an ant problem has more to do with the property than with the town. Two houses on the same street can have very different ant seasons, depending on what is growing around them.

Why ants come in the house after it rains

Ants are most active on a sunny day right after a heavy rain. The rain washes the aphids and their honeydew off the plants, and the ants lose their food supply. So they send scouts out to look for something else, and your house is close by. The scouts are after sugar: crumbs and the residue of spills. When one finds some, it leaves a scent trail and the rest follow it in.

If the ants turned up in your kitchen the morning after a storm, that is the reason. We went into it in why ants show up inside after it rains.

What to do about ants in the house before you call

Put the spray down. A repellent residue on the counter and the baseboards gets in the way of the bait treatment that comes later, and it can spread the colony in the meantime.

Use glass cleaner on the trail. It knocks the ants down right away and wipes out the scent trail the others are following, and it does not leave a repellent behind. Be careful on some surfaces because of the blue coloring.

Wipe up what they came for. The scouts are looking for sugar. Crumbs and sticky spots on the counter and the floor are what they are after.

Notice where the trail starts. Look at which wall the ants are coming from and what is growing outside it. That helps us find the source.

What professional ant control does differently

The goal of ant control is the colony at its nest, not the ants on the counter. That starts with knowing which ant it is. One of the most common small ants in our area is the odorous house ant, and it is sensitive to chemicals. Hit it with the wrong product and you have two problems where you had one.

Treating it calls for baits that have not been contaminated by other products, and for non-repellent liquids that are slow-acting and long-lasting. Because the ants do not avoid them, the treatment reaches the colony instead of scattering it.

We also look for the reason the ants are there: where they are getting in, and what around the house is feeding them. Sometimes the answer is in the flower bed. At New River Pest Control LLC, ants are part of our general pest control service, the same as spiders. For a home that deals with ants year after year, our quarterly and bi-monthly treatment plans are there to minimize pest activity inside the house year round.

Ant control in Dublin, Wytheville and the counties around the New River Valley

Much of our work is outside Blacksburg and Christiansburg. We handle ant control and general pest control for homes and businesses in Dublin and the rest of Pulaski County, a short drive from our home base in Radford, and in Wytheville and the rest of Wythe County. We also work through Carroll County, Bland County, Giles County, Craig County and Riner, as well as in Blacksburg and Christiansburg.

If the ants are back and the spray is not working, call or text (540) 818-9375 for a free phone quote. Tell us where you are seeing them and what you have already used, and we will get to the root of the problem.