“There are ants everywhere. They are crawling up and down the trees and they have trails all around the outside of the house. Sometimes they get in the kitchen or other parts of the house.”

That’s how my office phone has sounded lately!

Argentine ants are non-native ants that first entered the US at New Orleans in the late 19th century – which means they have been here longer than fire ants! Although they have no sting, Argentine ants are so aggressive and become so numerous that they can displace fire ants as well as other ant species. Argentine ants especially like shady landscapes that have lots of trees and shrubs.

They don’t build visible mounds like fire ants. Instead, they will have hundreds of small, inconspicuous nests in protected areas such as under flower pots, under piles of leaves or mulch, under bark of dead trees or under any debris lying on the ground.

For landscapes with heavy populations, successful control is best defined as just being able to keep them out of the house. In most cases it is not really practical to attempt to completely eliminate Argentine ants from the landscape. There are methods and tools that can be used around the outside perimeters of buildings to help keep indoor invasions to a minimum. These include cultural practices such as pruning limbs and shrubs that touch the building and keeping debris, mulch and leaf litter to a minimum around the immediate exterior of the building. Argentine ants do not take fire ant bait well and even the baits that they do take do not provide very good control.

If heavy outdoor populations are causing continuous re-invasion of your home, try applying treatments of residual insecticide to a 3 to 10 foot wide band around the perimeter of your house. These perimeter treatments can help control any nests located in the area and control or discourage foraging workers from nests located farther away from your home.

Examples of active ingredients used in insecticides labeled for perimeter treatments include: bifenthrin, carbaryl, cyfluthrin, deltamethrin and permethrin. Read and follow the label directions carefully. Some labels allow treatment of a portion of the outer wall of the home and around doorways and windows, while others do not.