Fire ants are on my mind (and at my job), so I’m sharing this previously published article by our Consumer Horticulture Agent, Michelle Wallace.    -Ann Barnes

(photo: NCSU)

By Michelle Wallace

Lately the calls have been coming into the master gardener office with requests for information on getting rid of fire ants. While fire ants have been in Durham for a few years now, many have not had to confront them until recently, especially if you live north of I-85. It only takes one bad experience to know the importance of managing fire ants in the landscape. Not sure about what kind of ants they are? Well take a long stick and poke at the mound, if they’re fire ants, they’ll swarm the stick to attack you, and if you don’t drop that stick you have pustules at ever place you were stung. Most of the other ant species are none aggressive and won’t swarm or try to attack you. They’ll just continue to go about their business.

While red imported fire ants are an unwelcome nuisance, it is important to remember that ants in general are considered beneficial insects and help in the degradation of waste and consumption of other insects. Fire ants have a particular affinity for greasy foods so it is important to keep areas both outside and inside the house clean since they know no boundaries when foraging for food. It is also helpful to know that native ants will defend their territory and will help to prevent red imported fire ants from spreading. For this reason, research studies now recommend spot treating each mound instead of trying to eradicate all fire ants by broadcasting baits over large areas.

Fire ants mounds contain ants of several sizes ranging from 1/8 to 1/3 of an inch. The mounds themselves vary in size and shape, but can get very big and deep with upwards of a 100,000 ants. Every spring and summer winged male and female ants will swarm in the air and mate. After mating the females become queens and start new mounds. Many will not survive, but many do and begin new mounds as far out as 10 miles from the original mound! If the new queen survives she will shed her wings and burrow down into the ground and begin laying eggs. In the fall, those new mounds will begin to appear, which is why we are noticing so many new mounds right now.

The good news is that fall is a great time to begin managing the fire ants. They are foraging for food and as the temperatures decrease their food sources are reduced making fire ant baits when properly applied effective. The goal is to kill the queen. While she lives she will continue to lay hundreds of eggs daily. It can take several weeks to kill all the ants in the mound.

Liquid drenches are another method of eliminating fire ants in a mound. Drenches are recommended for high use areas where the chance that someone will be stung is increased. Drenches typically work by contact. Fire ants that come in contact with the liquid drench pesticide immediately die. The challenge of this method of control is that there are no guarantees that the queen will come in contact with the pesticide and die. If the queen does not die, the mound will survive. Wow, sounds like the makings of a movie “Fire Queen Strikes Back.”

While you may be successful in killing the fire ant mound, monitoring for future mounds is very important. Don’t expect 100% control. There will always be new queens out there starting new mounds.

For more information about fire ants or to positively identify the fire ants contact the Durham County Master Gardeners at 919-560-0528 and request Insect Note – ENT/rsc-35 or search http://www.ces.ncsu.edu/depts/ent/notes/Urban/ifa.htm#biology .

* Remember to always read and follow the directions on a pesticide label before applying pesticides of any kind.

(Ed. note: There are organic options for control of fire ants. Please see this article for more information on organic control, including types of products available. Before trying home remedies, please read this post from our national Extension blog to see which ones have been proven ineffective.)