How To Spot And Get Rid Of Field Ants

Ants: They're creepy, they're crawly, and they're generally a nuisance. They can also be tough to get rid of, depending on the species. Field ants (Formica spp.), also known as thatching ants due to the large, thatched mounds they create and nest in, aren't usually found in homes — but that doesn't mean they can't cause trouble. Luckily, field ant colonies can be easily identified by their large mounds, which can reach sizes of four feet wide and up to two feet tall. 

While field ants don't pose a real danger to humans or pets — besides the occasional annoying, stinging bite when aggravated — their mounds can be a real eyesore in gardens, lawns, and around landscaping features. Field ants aren't much of a problem when they nest away from humans and manicured yards, but their large mounds can prove to be an eyesore and may interfere with healthy grass growth. In some cases, certain species of field ants will inject formic acid into the roots of nearby woody plants. Many species of ants, including field ants, are also attracted to common garden features like rock and pebble landscaping. Because field ant colonies can survive for 10 years (or even longer) it's important to take action when you find one to avoid damage to your lawn and other landscaping features.

Field ants are actually a genus of ants containing multiple species. At first glance, they look very much like other types of ants and are often confused with the much more destructive carpenter ant (Camponotus spp.). Field ants are the most common ant in most North American yards and gardens and can be black, brown, tan, or some combination of colors. A field ant colony is generally very easy to spot, thanks to the large mounds that the ants build to house their queen and eggs. In lawns, field ant nests tend to be shorter in height, usually staying below the height of the grass, but they can sprawl for several feet.

The ants like to nest in loose soil and commonly build their mounds with a variety of natural materials like twigs and dried leaves. Field ant mounds can sometimes be mistaken for fire ant nests, which are often similar in size and appearance, but made out of soil rather than leaf debris. You can also find field ant mounds in more secluded areas like underneath rocks or logs. Once you've narrowed down what kind of ant is plaguing your home, it becomes much easier to get rid of it.

Field ants aren't much of a problem when they nest away from humans and manicured yards, but their large mounds can prove to be an eyesore and may interfere with healthy grass growth. In some cases, certain species of field ants will inject formic acid into the roots of nearby woody plants. Because field ant colonies can survive for 10 years (or even longer) it's important to take action when you find one to avoid damage to your lawn and other landscaping.

The key to eradicating field ants from your yard is this: kill the colony's queen by using an insecticide that includes cyfluthrin, deltamethrin, bifenthrin, carbaryl, or permethrin. You must make sure the insecticide permeates deeply into the ground in order for it to be effective. Because field ant nests can be so large, the first step in the extermination process is to rake or sweep away the thatched above-ground mound that the ants have built. If you don't remove enough debris, your chosen insecticide may not penetrate far enough into the underground nest to kill the queen. Next, use a long rod or dowel to make several deep holes in the ground where the nest is located. This should ensure that the insecticide reaches the queen. 

Apply your chosen insecticide according to the directions on the label. You will need to saturate the ground on and around the nest, so take necessary precautions to keep pets and children away from the area. To prevent field ants from coming back, make sure to control populations of pests that produce honeydew, like aphids, on nearby plants. Aphids and ants can both wreak havoc on your garden, and field ants feed on the sweet honeydew excreted by these bugs, often building their nests nearby.