Where fire ants come from?

Pest fire ants, the black and th red imported fire ant, are native to central South America and were introduced into the continental Us through the port of Moblie; the black, around 1918, the red around 1930.  Presently, the black imported fire ant is found only in northeast Mississippi and northwest Alabama.  The red imported fire ant is foudn primarily in the southeastern quarter of the continental US.  Red imported fires ants are the primary pests.  There are several native fire ant species. 

How do they spread?

Imported fire ants spread (1) through transport of sod or nursery stock that is infested with mated queens or colonies (this is hwy nursery stock and sod sold outside the fire ant area must be certified as fire ant-free); (2) queens mated in the air fly, are blown or are transported when they land on vehicles, into new area; (3) flooded colonies form rafts that flowat to new areas.

What limits the spread of imported fire ants?

Cold temperatures still limit the spread of imported fire ants inot more northern agreas.  The quarantine (certification of plant material shipped outside the fire ant zone) also slows the spread.

How does a fire ant colony begin?

Colonies are established by mated queens after a mating flight.  Older colonies produce winged reproductive forms (males, and females or "queens").  Most mating flights occur in the spring after rains on warm days.  Mating occurs in the air, and mated queens land, lose their wings days.  Mating occurs in the air, and mated queens land, lose their wings and seek a place to hide (90% or more queens are preyed upon by frogs, lizards, other ants including fire ant workers already in the area, etc.).  They dig shallow depressions, and lay a few eggs from which workers (all sterile females) hatch.  These workers care for the queen, egg production increases, and thus they colony begins.  In some areas, 'multi-queen" colonies have been discovered in whwich there are more than one egg-producing queen per colony.  In these cases, all queens must be eliminated in order fot he colony to dies.  As long a a queen and a few workers survive the colony will live.

What is the difference between single­queen and multiple­queen forms of the red imported fire ant?
Single­queen (monogyne form): only one queen per colony or mound; slightly larger workers; members of colonies are territorial; mound densities usually 20­80 mounds per acre; fewer ants per acre.

Multiple­queen (polygyne form): dozens of queens per colony; smaller average worker ants; colonies are interconnected; mound densities 100 to 1,000+ per acre; more ants per acre.

How long do fire ants live?

How lnog worker ants live depends on their size.  The smallest workers live a month or two; medium-sized workers live two or three months; the largest workers may live three to six months.  Queens live in nature two to six years.  Males don't live long after they mate and fall to the ground.

What do fire ants eat?

Almost anything; but fire ants feed primarily on other insects.  Workers sting other insects and then tear them into manageable pieces which they take back into the colony.  Fire ants are attracted to the oils in insects, worms and seeds.  This is why oils are used as attractants and insecticde solvents in fire ant baits.  Although fire ant workers can chew, they can only swallow liquids.  Solid foods that are brought back into the colony are digested by they fourth stage larvae (immatures) and fed back (fire ants feed each other) to other members of the colony.  Chemical messengers (pheromones) are mixed with the food as it is passed around , especially by the queen. 

Why do mounds relocate?

Disturbing mounds (mowing, etc.) may cause mound and/or colony relocation.  "Over-dosing" with insecticides may cause relocation (most insecticides at high doses may act as repellents).  It is believed that disturbing the mound before treatment can cause relocation.  Sometimes fire ants just move.

How deep do colonies go into the ground?

That depends on the age and size of the colony, soil texture, and how far down the water table is located.  Mounds are not necessary for colony survival as long as there is a dark, moist area for protection of the queen.  These types of colonies are sometimes found in walls and other parts of structures.

How can I tell the difference between fire ants and termites?
Although most ants are recognizable, some forms of winged ants are often confused with termites, especially during the termite swarming season. The front pair of wings on ants are larger than the hind pair, while the four wings of termites are approximately the same size. Ants have "elbowed" antennae and a "thin waist," being narrow between the thorax and hind abdominal segments. Termites have the thorax and abdomen broadly connected and their antennae are straight and hair­like.

Why do fire ants appear to sting at the same time?

Fire ants are sensitive to vibration or movement and tend to sting when the object they are on moves. The ants swarm up a person's leg and when one ant stings that person jerks or moves. This triggers many of the other ants to sting in response. Thus, it appears they all sting at the same time, and most do.

Is their sting lethal?

Only to a very small portion of the population who experience severe allergic reactions.

What should I do if I get stung?
There really isn't much you can do, except watch the area for excessive swelling, itching or redness or other symptoms like shortness of breath, thickening of the tongue, sweating, etc. that could indicate a systemic allergic reaction. Treat stings as you would stings of other insects and keep stings clean and in tact to avoid getting secondary infections.

What if I have an allergic reaction?
Seek medical help immediately!

Are they as lethal as killer bees?
Kind of like comparing apples to oranges. They both attack en masse and can both cause fatal allergic reactions, but that's where similarities end. Africanized bees can overwhelm and kill even healthy, non­allergic people, but encounters are rather rare. Fire ants can't overwhelm a healthy, mobile person and even hundreds of stings are rarely fatal. But, fire ant mounds are extremely common. So the chance of being killed by bees is higher if you come across them, but the chance of being killed by fire ants is higher only if you are highly allergic or cannot quickly get away from them. The chances of either are very small.

Can fire ants be eradicated completely?

Red imported fire ants cannot be eradicated completely with methods available today. They can be eliminated temporarily from small areas, with proper control methods. Their biology and spread make it economically, technically, and ecologically impossible to eradicate them from larger areas.

What is the best method to control fire ants in my yard?

Read Circular ANR-175,"Imported Fire Ants In Lawns, Turf, and Structures" for details.  Generally, control strategies depend upon such factors as the size and use of the site, how frequently and how many people use it, the availability and expense of labor, and personal preference.  On home lawns, fire ants can be eliminated at any given time; the problem is that reinfestation occurs, so control involves an ongoing effort.  Mound treatment alone is usually most pratical on small lawns.  Larger and frequently-used areas may be broadcast-treated, or treated with a combination of broadcast bait treatment pluse contact-mound treated. 

What is the "Two­Step Method" for controlling imported fire ants?
One proven method of reducing imported fire ant populations in heavily­infested home lawns and ornamental turf is called the "Two­Step Method" of fire ant control. Briefly, it's the: 1) once or twice per year broadcast application of a bait product (e.g., Amdro®, Logic®, Award®, or Ascend® and others) and waiting several days to a week before; 2) treating nuisance mounds, using an individual mound treatment, such as a dust, granule, bait or drench insecticide. Otherwise, wait for the bait treatment to take effect. This method reduces the over­reliance on use of individual mound treatments and is suitable for treating larger areas.

Why tackle fire ants in the fall?
An ideal time to apply bait­formulated fire ant insecticides is from late August through October to allow the baits to reduce fire ant populations over the winter.

It's been dry and I don't see them. Are they still around? Why should I treat them

now?
The ants are still there, just not making mounds because of the heat and drought. They are deep in the ground during the day and come out to forage at night. Ants are often more of an indoor problem now, as they come in after food and water. Treating now can be very effective since the ants are weakened anyway. Using individual mound treatments during hot, dry conditions is not a good idea because mounds are absent and/or ants are deep. Baits can work quite well if the ants are out foraging to pick it up. It is best to treat in the late afternoon or evening. You will know if thunderstorms are a possibility, there is no dew on the grass, and the bait will not have to sit in the hot sun all day. Most of the bait will be picked up by morning.

Which bait do I use? Baits take too long? Baits don't work.
The key to using baits is patience. Applied properly and using a fresh bait product, a broadcast application will give 80% to 90% control, rarely 100%. For instance, Amdro® is the fastest­acting, giving maximum control in 3 to 6 weeks. Logic® or Award®, when applied late in the year, may take several months to provide maximum control, but will suppress ant colonies for a year or more. One approach, for example, for heavy imported fire ant infestations is to treat with Amdro® first for fast knockdown, then come back with Logic®/Award® for longer durations control as ants start to re­infest the area some months in the future. Other baits include Siege®, Award®, Ascend®, and Raid® Fire Ant Killer.

We tried using those baits, but they don't seem to work. I'd like to use something safe. What do you recommend?
The baits do work when used properly. The thing to remember is the ants collect the bait as a source of food. Baits will go rancid in a relatively short time as does other food that contains oil. Additionally, putting the bait out at the right time of day, and at the correct rate (1 to 1 1/2 lb/acre) is critical. If the ants are not actively foraging, they will not pick up the bait. The best times to make bait applications generally are mid­morning after the dew has evaporated, or late afternoon on hot days when the air begins to cool. Always read and follow closely the directions provided on the product label before using any pesticide.

If I put out the bait, how often should I reapply, and when?
The fall application is important because it will help suppress ants by the following spring. Reapply when imported fire ant mounds begin to appear again. Generally, if you make a spring application, suppression should last until that fall, when the next application should be made.

I can't afford to treat for fire ants.
If you have a 1/4­acre lot (100 x 100 feet, 70 X 150, etc.) you would need less than 1/2 pound of a bait. A pound costs less than $10 and you would get two applications with some to spare. It would likely get ants down to a level you wouldn't notice within a month or so. For faster control, do the Two­Step Method and treat individual nuisance mounds after broadcasting a bait product. A can of Orthene® or bag of diazinon or Dursban® will cost you about 30 cents per mound. It's really not that expensive if you do it right.

What is the safest product for my children, pets, chickens, etc.?
The main concern is to not put a toxic pesticide in high enough concentrations where kids and animals can get at it. Always follow carefully the directions provided on the product's label. You can use a less toxic material and apply it so that there will be little contact. Baits, when broadcast, not only have very low toxicity, but are scattered very thinly and fall down in the grass where few things but ants can get at them. Granular and dust products will remain on the soil surface where potential contact can occur unless the material is watered in after application. Drenches may be a better individual mound treatment choice. Keep animals and kids away from treated areas as directed or until vegetation and the soil surface is dry.

Are there any biological controls out for fire ants? I heard about a fly that is supposed to kill fire ants, what's the story on that?
Auburn University and the United States Department of Agriculture are conducting research on the phorid fly as one of several potential biological control agents for helping to control fire ants. However, this research is in the beginning stages. We may be years away from any type of control these flies may provide. Even in South America where the imported fire ants and parasitic flies come from, the flies only affect about 3% of the ants in a colony. Some biological control agents that have already been marketed include predaceous mites, parasitic nematodes, and the fungus called, Beuveria bassiana. Scientific studies are being conducted to evaluate the effectiveness of some of these natural enemies, but others remain untested or have not been shown to be highly effective when used as directed.

Why can't I just pour gasoline on the mounds?
Don't do it! It probably does not kill the entire colony much of the time, it is dangerous to handle, it kills any plant material it touches, and at least some of the residue remains in the soil and may leach or run off into ground and/or surface water.

Why don't we use Mirex?
Mirex was an effective ant killer, but it was one of the more persistent compounds ever made. Mirex belongs to a group of chemicals that have mostly been banned from sale or use. Their ingredients, or their degradation products, accumulated in biological systems.

Can I purchase and spread Fire Ant bait on my yard without a "Private Applicators License"?
On your own property or on other private property as a volunteer (one who is not getting paid for their services), non-licensed private individuals can apply non-restricted bait products. None of the baits are restricted products, but several may only be obtained from distributors to professional pest control operators or landscapers. Over-the-counter baits at consumer retailers are limited to Amdro and Combat (hydramenthylnon); Raid Ant Bait (abamectin) - which is now old product; Spectracide Ant Bait (pyripoxyfen) which is formulated at 1/10th "conventional" formulation concentration and costs 10 times as much to apply as conventionally-formulated products.

This information was prepared by Dr. Patricia P. Cobb, Professor Emeritus, Department of Entomology and Plant Pathology, Auburn University and the Texas Imported  Fire Ant Research and Management Project