Friday, October 12, 2012

Fire Ants Rule? Yeah, Right!

             This is the time of the year in the Gulf Coast area of Texas when temperatures begin to moderate and you and your family spend a lot of time in your yard. Do you feel that fire ants have taken over? The best way to manage fire ants is to follow a management plan developed for your property that you follow each spring and fall.  Fire ant management is a planned activity not a reaction.
            The red imported fire ant (Solenopsis invicta, Buren) (Hymenoptera: Formicidae) loves the warm humid air, moist soil in planting beds and turf grass. The months from April through July and late September through October usually presents ideal conditions for fire ants to work their mounds and cause problems for anyone who ventures outside.

Red Imported Fire Ant (Solenopsis invicta, Buren) (Hymenoptera: Formicidae)
             Fire ants like to nest in open, sunny yards that are mowed and watered regularly. They will nest in vegetable gardens for the moisture supply, in newly planted tree rings, in sidewalk cracks and next to building causing damage and unsightly mounds.   They are attracted to pet bowls, utility boxes, and occasionally, they invade homes in search of food, water and shelter.

Fire ant mound in sidewalk crack
             During the spring and fall, fire ants become very active. Colonies move readily during this time, especially after rainfalls that leave standing water. Fire ants travel from yard to yard.  They do not respect property lines. They are also easily dispersed during their periodic mating flights that occur after any rain event.
            Did you know that the fire ant queen lives for 2 to 5 years and can produce up to 1,000 eggs per day? Also, remember that a large percentage of the mounds in Texas have multiple queens, meaning that there is no territorial behavior. This results in many fire ant mounds per acre or per yard!

Fire Ant Mounds in Pasture
            Because most of our mounds have multiple queens and may be spread over larger areas than we actually see, just sprinkling a product over the top of the mound may not control the whole colony. For individual mound treatments to be effective, you have to locate and treat every colony.  It takes about an hour to thoroughly examine an acre of land for fire ants and mark the colonies for treatment. Mounds in clay soils have structure and are usually easily recognized, but sandy soil mounds are more flat which makes them hard to locate.  It is not necessary to mark mounds when fire ant bait is broadcast. Foraging ants in even the smallest, most well-hidden colony will likely pick up an effective dose of broadcast bait resulting in colony control over large areas. In most cases, baits are the least expensive way to control fire ants and very little labor is required for the application. 
          The Texas A&M AgriLife Extension Service recommends using an area-wide treatment strategy to manage fire ant populations.  One of these strategies is broadcasting a bait insecticide product over your entire yard usually between late August and mid-October, then treating individual, problem mounds with an approved mound drench, granule, or dust insecticide. The Two-Step Method works best in fully infested areas (five or more mounds per quarter-acre of yard). 

How to Win the Battle with Area-wide Treatments 
             Unless you mount a coordinated effort with your neighbors, you will continue the battle and expense of trying to control fire ants. The only way to tackle this problem is for everyone—neighborhoods, communities, and organizations—to work together.
             Many communities and neighborhoods across Texas are working together to successfully manage fire ants. These neighborhood-wide treatments are safer for the environment because less pesticide is actually used to control the ants.
             One proven approach to effectively manage fire ants is called the Two-Step Method. A second program, also safe to children, pets and the environment, is to have a granular product containing fipronil broadcast over your yard once a year, preferably in the early spring, by a Pest Management Professional.
             Two-stepping begins with broadcasting a fire ant bait product over your entire yard sometime between late April and May or late September through October. Then you treat individual, problem mounds with an approved mound drench, granule, or dust insecticide. 

Step 1: Baits 

             Fire ant baits consist of pesticides and processed corn grits coated with soybean oil. Worker ants take the bait back to the colony, where it is shared with the queen which then either dies or becomes infertile.  Fire ant bait products currently available consist of one or more of the following active ingredients, abamectin, hydromethylnon, indoxacarb, pyriproxyfen, or s-methoprene.  Baits are slow acting and require weeks to months to achieve 80% to 90% control. They can be used to easily treat large areas effectively and contain extremely low amounts of toxins.
             I consider them to be one of the more environmentally sound ways of managing a fire ant population. Broadcast baits are generally applied with less risk to the applicator and environment than almost any other type of insecticide treatment. Broadcast baits introduce less total insecticide with fewer toxic active ingredients into the treated area.  Another favorable environmental aspect of broadcast bait treatments is that fire ants quickly remove the bait product from the ground surface and carry it into their respective mounds. 

Introduction to fire ant baits video 

A list of these and other products can be found at:
Latest Broadcast on Fire Ant Control Products

For best results:

  1. Follow “broadcast” directions on label of fire ant bait product
  2. Use a fresh bait product, preferably from an unopened container.
  3. Apply baits with a hand-held seed spreader or other suitable equipment.
  4. Don’t apply baits mixed with fertilizer or seed. 
  5. Broadcast apply when the ground and grass are dry and no rain is expected for the next 24 to 48 hours.
  6. Broadcast apply when worker ants are actively looking for food, usually in late afternoon or in the evening.  To test, put a small pile of bait next to a mound and see if the ants have found it within 30 to 60 minutes.
  7. Apply the baits once or twice a year.
          Baits can be applied anytime during the warm season. Best times in the Houston area are late April/May and again in late September/October.  When applied at these times the fire ants are still foraging and it’s easier to predict weather patterns.

Step 2:   Individual Mound Treatments

            Chemical. About a week after the bait application, treat individual mounds in traffic areas. Chemical treatments come in the form of drenches, granules, or dusts. There are less toxic and non-chemical means of treatment that are widely available. Some have shown effectiveness in reducing the number of mounds.  Closely follow directions on the label. With dust products, no water is needed and they act fast. However, they leave a surface residue. Liquid drenches generally eliminate ants in mounds within a few hours and leave little surface residue after application. Granular products are relatively fast acting and usually require putting granules on and around the mound and then sprinkling 1 to 2 gallons of water on without disturbing the mound.
            Organic. Natural or organic methods include mound drench products containing plant derived ingredients (e.g. botanical insecticides), ingredients produced by microorganisms (e.g., spinosad), or biological control agents.

Alternative Area-Wide Treatments

             Granular fipronil: The introduction of granular fipronil products provides a one step procedure for fire ant control.  Fipronil granular products (TopChoice®, Taurus G™) are slow-acting, requiring 4 to 6 weeks from application to achieving maximum control). The active ingredient is a long-residual contact insecticide that has provided season long control in research field trials (see and search the site for “fipronil” to find reports).  Fipronil granular formulations have to be applied by a Pest Management Professional.  They contain low concentrations (sub-lethal dose) of the active ingredient and provide slow-acting (four weeks from treatment to maximum control) and long-lasting (season long, up to 12 months) elimination of colonies in treated areas. The fipronil product should be applied in Late February or March.  If the fipronil product is applied later in the spring or summer, an application of a fast acting fire ant bait may be necessary to reduce the fire ant population before the slower acting fipronil product is applied. 
            You should be aware that as a non-repellent contact insecticide, foraging ants from adjacent untreated areas can enter fipronil treated areas and remain active on the surface following application.  Fire ant mounds may not be present but the foraging ants may be.  This makes granular fipronil a poor choice as a barrier treatment around structures (5 to 10 foot swath) to protect them from fire ant entry, and reportedly causes some control failures of foraging ants in lots with large houses and small lawns.

For Best Results:
  1. Contact your Pest Management Professional and have them apply the fipronil product in early spring (late February March)
  2. The product will be spread at a rate of 2 lb product/1000 sq ft.
  3. Evenly broadcast product over the area to be treated.
  4. The treated area should be lightly water after application.
  5. This is a once a year treatment.  
If you have questions about fire ants and their control or about specific products please contact me at the Texas A&M AgriLife Extension Service, Harris County Office, 218-855-5600 or e-mail at .
For more information regarding fire ant management visit these websites for additional information on fire ants: 

Especially these Extension publications found at:    Fire Ant Fact Sheets and Publications 

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