Do You Have Angry Fire Ants Again This Spring?

— Written By Glenn Detweiler and last updated by Judy Moore
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Red Imported Fire ants aggressively attack anyone or anything that disturbs them or their mound, as too many Lincoln County residents have discovered first hand. The fact that their natural enemies are not present in North Carolina in any numbers, is allowing them to have more success as pests than they have had even in their native land of Brazil.

Red imported Fire Ants (RIFA) were accidentally introduced into the United States from Brazil around 1930. Fire ants are reddish brown at a glance and range in length from 1/8 to 1/4 inch. In addition to their appearance, and aggressive behavior, they are identified by their painful sting, which produces a small white bump on the skin within 8 to 24 hours.

Fire ants cause economic losses in yards, gardens, and agriculture. They construct unsightly mounds, which cause difficulty during mowing and can damage farm and lawn maintenance equipment. In addition, fire ants are attracted to electrical fields.

Short circuits and damage to electrical equipment can be the result of fire ants. However, their impact upon our lives can be minimized by knowing their eating and living habits. With patience we can apply mechanical, biological, and chemical controls when these insects are most vulnerable.

The most effective chemical control methods for imported fire ants result in killing the queen or prohibiting her from producing more worker ants. The queen does not work to increase the nest, or collect food. In fact, she stays in the nest, often down deep and protected. Interestingly, their mounds have no entrance and exits holes like most ants hills. All access is through tunnels surfacing around 2 to 3 feet away from the visible part of the mound. The queen is relocated in the ant mound based on the temperature of different levels. If danger is sensed by the workers she is moved to the bottom of the mound or moved into one of the tunnels that go horizontally away from the mound.

Scientists have worked to figure out how to get poison to the queen to kill her or at least prevent her from reproducing. In order to trick the worker ants into carrying poison to the queen, scientist mix grits and vegetable oils with poison. The worker ants carry it into the colony’s mound where it is processed by other workers to be fed to the queen.

When ants sting us (it is the sting, not the bite that causes problems), or our children, grandchildren, and/or pets, we want a poison that will kill the ants now, visibly, and dramatically. We know the poison is “working” because we see dead ants. But the queen is down in the nest and protected. She continues to produce more ants, and often a second queen in the nest will “bud-off” to form another colony making the problem worse. This explains why Extension agents so often get calls that people are treating the ants, but seem to be just getting further and further behind. Knowing that worker ants carry food into the mound for the queen, lets us know that we need to use them to carry poison to her and feed it to her. You actually WANT the workers to  LIVE long enough to do this.

There are now fire ant poisons that will not kill workers immediately, but instead lets them live long enough to thoroughly poison the queen. These materials are labeled as “Fire ant baits”. You need to be sure that the material is specifically for fire ants, and that it is specifically labeled “bait”. Other materials, including most products labeled granules (not baits) are contact pesticides. They kill the workers quickly instead of allowing them to take the poison to the queen.

Unfortunately, the bait treatments can take up to 5 weeks to destroy the colony. To get the benefits of bait, along with the speed of a contact pesticide, you can use the “two-step” method. Using this method, you apply the fire ant bait, and then about a week later, apply the typical contact pesticides, or “fire ant killers” to kill large numbers of workers, knowing that now, they have already had plenty of time to poison the queen with the bait you gave them.

Follow these instructions:
1) Apply bait when foraging ants are actively searching for food. Try a greasy chip 3 feet from an active mound. If ants are seen on it within 10 to 30 minutes, it’s a good time to apply bait.
2) Do not disturb mounds before or during bait application. (Getting them to rush out of the nest puts them into defensive, more than into bait collecting mode.
3) Apply bait when the ground and grass are dry and rain is not expected for the next 12 to 24 hours.
4) Use fresh bait, preferably from an unopened container or one that has been tightly sealed and not stored long. Worker ants will not pickup rancid bait.

READ AND FOLLOW LABEL INSTRUCTIONS. Make certain the area you plan to treat with the bait product is listed as acceptable on the label. It must be applied only in those areas. Yards have many fire ant control bait options, however only a few baits are labeled for use in vegetable gardens and agricultural areas such as cropland, pastures, and orchards.

The Lincoln County Cooperative Extension Service (an extension of North Carolina State University) can provide you with a comprehensive list of the available chemicals and can answer questions that apply to your specific situation. For specific questions on any pesticide call Tom Dyson for gardens and yards, Andrew Scruggs for crops and agriculture at 704-736-8461, and Glenn Detweiler for livestock & agriculture applications at 405-219-1902. We are happy to do a presentation of fire ant information and their control at meetings of any organizations in the county. Just contact us.