Fire Ants Rule? Yeah, Right!
Dr. Paul Nester
Extension Program Specialist Integrated Pest Management
Texas AgriLife Extension Service, Houston Metro Area
Do you spend a lot of time in your yard here in the Gulf Coast area of Texas? Do you to feel that fire ants have taken over? The best way to control fire ants is to follow a management plan developed for your yard.
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.
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.
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!
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.
The Texas 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, bait, 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’s 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 insecticide 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, bait 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.
A list of these and other products can be found at: http://fireant.tamu.edu/controlmethods/products/latest_greatest/pdf/nester-fireantbait2012.pdf
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, baits, 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 http://fireant.tamu.edu 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 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. It will be 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 please contact Dr. Paul R. Nester, Extension Program Specialist – IPM, Texas AgriLife Extension Service, Harris County Office, 218-855-5600 or e-mail at firstname.lastname@example.org. He is part of the Fire Ant Project Team of the Texas Imported Fire Ant Research and Management Plan, Texas A&M AgriLife Extension Service, Texas A&M University System. The team was established to find long term solutions to our states imported fire ant problem and to educate people on the best available methods to manage these pests.
Especially these Extension publications found at:
Managing Red Imported Fire Ants in Urban Areas (B-6043):
Broadcast Baits for Fire Ant Control (B-6099):
Fire Ant Control: The Two-Step Method and Other Approaches (L-5496):
Visit my blog at: doctorfireant.blogspot.com