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B-6076 |
Managing Red Imported
Fire Ants in Agriculture

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Bastiaan M. Drees,
Professor and Extension Entomologist, Fire Ant Project Coordinator, The Texas A&M
University System
Charles L. Barr,
Extension Program Specialist - Fire Ant Project, The Texas A&M University System
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Donna R. Shanklin,
Assistant Extension Specialist - Natural Resources, Cooperative Extension Service,
University of Arkansas
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Dale K. Pollet,
Extension Entomologist, Cooperative Extension Service, Louisiana State University
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Kathy Flanders,
Extension Entomologist, Alabama Cooperative Extension System, and Assistant Professor, Auburn University
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Beverly Sparks,
Professor and Extension Program Coordinator - Entomology, The University of Georgia
Cooperative Extension Service
Integrated Pest Management (IPM)
Cattle Production Systems, Pastures and Rangeland
Poultry Houses, Livestock Barns and Feedlots
Field Crops and Commercial Vegetables
Fruit and Nut Orchards, Vineyards and Blueberry Plantings
Fish Farms and Production Aquaculture
Table 1. Insecticides registered for control of red imported fire ants in agricultural lands.
Worksheet 1. Are fire ants costing your cattle operation money?
Worksheet 2. Are fire ants costing your hay operation money?
The red imported fire ant, Solenopsis invicta Buren, is an
introduced species that arrived in Mobile, Alabama from South America during the 1920s.
This ant species has had an enormous effect on the southeastern United States, and
continues to spread into areas of North America with mild climates and adequate moisture
and food. Approximately 270 million acres in the southeastern United States are currently
infested. (See national map of fire ant infested and quarantined counties.) A second
exotic species, the black imported fire ant, Solenopsis richteri Forel, and hybrids
between S. invicta and S. richteri occur in northern Alabama, and portions
of Georgia, Mississippi and Tennessee, but not farther west.
Fire ants cause many problems in agriculture. They form tall, hardened mounds in clay soils, which can damage equipment and slow down operations. Ant stings can cause medical problems for field workers. The ants have an affinity for electrical units and utility housings and structures, where they can cause equipment failures. Worker ants feed on some seeds and seedlings (sorghum, corn, small grains, forages, etc.) and can cause stand failure. Fire ant mounds can rapidly increase in number after agricultural lands are disturbed by mechanical operations or pesticide use.
Fire ants prey on a number of other insects and arthropods, including boll weevils, many species of caterpillars, flea larvae, ticks and chiggers, as well as beneficial insects such as green lacewing larvae. They will also tend some species of sucking insects (aphids, mealybugs) to obtain the sugary solution (honeydew) these insects excrete. The red imported fire ant has displaced many native ant species and reduced food used by some wildlife. Fire ants are a threat to newborn livestock and wildlife, especially animals on the ground or those nesting in low trees. Their multiple stings can cause serious injury or even death. Although the research is not conclusive, populations of some wildlife species may be dramatically reduced.

Like other ants, the fire ant is a social insect. Colonies live in mounds of dirt that may be more than 18 inches high. Mounds are often found in open, sunny areas. Periodically, winged reproductive male and female ants leave colonies on mating flights. Mated females (queens) can fly or be carried by winds for miles. When they land they start new colonies. Ants develop from egg to adult in about 30 days, going though four larval stages and a pupal stage. There may be hundreds of thousands of worker ants (sterile female ants capable of stinging) in a mature colony.
There are both single queen (monogyne) and multiple queen (polygyne) colonies. The single queen form may build 40 to 80 colonies per acre, while the multiple queen form can build 200 to 800 or more mounds per acre. Worker ants from multiple queen colonies are not territorial and move freely from mound to mound. The opposite is true of workers from single queen colonies.
Fire ants disperse naturally through mating flights and mass movement of colonies. When land is flooded, colonies form a mass of floating bodies and float to new locations in flood water. Fire ants can travel long distances when newly mated queens land on cars, trucks or trains. Shipments of hay, nursery stock or soil from an infested area may relocate entire colonies or nests.

Because fire ants are easily transported in nursery stock and soil, the United States Department of Agriculture (USDA) developed a quarantine program in the 1950s. This quarantine is designed to slow the spread of imported fire ants by requiring proper inspection and treatment of all nursery stock, turfgrass, hay and other articles shipped out of quarantined counties. Contact your states Department of Agriculture for specific information about complying with quarantine regulations.

Integrated Pest Management (IPM)
This bulletin describes site-specific, goal-oriented management programs for dealing with fire ants in agricultural areas. Where applicable, you should select programs that use a combination of non-chemical and chemical methods that are effective, economical and least harmful to the environment. The goal of fire ant management is to prevent or reduce problems caused by unacceptably high numbers of fire ants.

Every effort should be made to target control only at the red imported fire ant. Preserving and encouraging native ant species that compete with fire ants for food and resources is thought to be the best long-term solution.
Integrated Pest Management (IPM) is a concept used in many areas of agriculture to help producers determine whether the cost of pest control can be offset by production gains, before treatments are applied. The first step in any IPM program is to find out what losses are occurring and how much those losses actually cost. It is up to the individual to decide what counts as a fire ant-related loss and to put a value on that loss. If there is some question, it is often a good idea to make two assessments-one for definite losses and one for losses that might be attributable to fire ants. Then you have a range of costs within which treatment expenditures can be justified.
In theory, management efforts should begin only when the monetary loss caused by red imported fire ants equals or exceeds the cost of controlling them. This is the Economic Injury Level (EIL). The Economic Threshold (ET) is the level at or below the EIL at which action is justified to prevent economic losses. Losses caused by imported fire ants, however, are erratic and unpredictable, and are best estimated from experience on a given property.

Determining Losses
In a recent survey, ranchers said that fire ant problems are widespread and costly, but vary tremendously from ranch to ranch, even within the same locality. As a result, no one management plan can be used in all situations. Losses must be determined for each individual operation and treatment plans tailored to minimize those losses at an acceptable cost.
Ranchers can make two common mistakes when estimating fire ant losses and deciding on treatments. First, they may not include every loss caused by fire ants that takes money out of their pockets. Dead and injured calves and infested hay bales are obvious losses. However, a shorted-out air conditioner or the cost of treating mounds around the childrens swing set also should be included, even though they are not directly related to the business part of the ranch. Survey results show, in fact, that electrical damage and pesticide expenditures are the two most common types of losses.
The second mistake involves treatment options. Fire ant eradication is not technically or economically feasible. Still, when many ranchers think of fire ant treatments they think of treating large expanses of land to try to kill all ants. At a minimum of about $15 per acre per year, treating large areas is not usually economical, although some methods can cut large-area treatment costs by up to half. What many ranchers fail to realize is that most fire ant problems occur on fairly small areas that can be treated rather easily and at a modest cost.
Worksheets 1 and 2 (pp. 17-18) can help you categorize and tabulate losses. The first is for cattle production, the second for hay production. Once you have an accurate estimate of losses you can choose which treatment options are best for you.
Some points to remember when estimating losses:

Management Strategies
Nonchemical: Nonchemical or cultural control methods can reduce losses while maintaining a stable ant population that will help suppress other pests (lone star ticks, filth breeding flies, etc.) and deter the multiple queen form. Nonchemical methods include:

Chemical: Chemical treatment can suppress fire ants in pastureland for $10 to $15 per acre per year. Chemical treatments do not eradicate fire ants, and the treatments need to be repeated periodically. Some bait-formulated insecticides also affect native ant species that compete with fire ants. However, in areas with 20 or more mounds per acre, using baits as part of the Two-Step Method method may be justified. In the Two-Step Method, a fire ant bait is broadcast once or twice a year. These treatments can kill up to 90 percent of the colonies within several weeks to several months. Hydramethylnon bait (Amdro®) takes 3 to 6 weeks and the effects last for months or until ants re-infest the treated area. Insect growth regulator baits containing fenoxycarb (Logic,® currently registered for horse pastures only; Award,® regis-tered for turfgrass areas) or s-methoprene (Extinguish,TM registered for pastures) require 2 to 6 months but suppress ants for more than a year. The second step in the Two-Step Method is to treat individual mounds that are a particular nuisance. Products containing carbaryl or Sevin® are regis-tered as fire ant mound drenches for pastures. Once the broadcast bait treatment has taken effect few individual mounds should need to be treated. Always read and follow the instructions on the products label.
Biological: There is great hope that in the future fire ant populations will be suppressed through the release of natural enemies from their native habitats in South America. One parasite being investigated is a phorid fly that develops inside the heads of ants. In theory, adult phorid flies looking for worker fire ant hosts suppress ant foraging and allow native ant species to compete more successfully with fire ants.
Imported fire ants on poultry farms can attack chickens and forage on broken eggs. Fire ant stings cause blemishes that can reduce the quality of poultry. Similar problems occur in animal feeding stations, barns and feedlots.
Treatment options:
Program 1: Poultry houses and egg farms (use a combination of the following suggestions)
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Program 2: Broiler houses and turkey operations
Program 1 for egg farms can be adapted to broiler houses and turkey operations if the products used are registered for this site, but be sure to treat only the outsides of houses so birds will not come into contact with insecticides. (see Step 5 above).
Program 3: Livestock barns and feedlots.
Red imported fire ants are considered beneficial insects in cotton and sugarcane production, and control is not recommended. In cotton fields, fire ants are effective predators of boll weevils. Fire ants can be sampled using the beat bucket method, whereby the terminals of cotton plants are beaten into a plastic bucket to dis-lodge insects. Insecticides usually are not needed for boll weevil control when an average of four or more fire ants is collected per ten terminal samples in mid- to late-season cotton. In Louisiana sugarcane fields fire ants prey on sugar-cane borers, Diatrea saccharalis (Fabricius). There, controlling fire ants increases the damage caused by the borers and the amount of pesticide that is needed.
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Fire ants occasionally feed on germinating seeds and seedlings of corn, sorghum, peanut, soybean, watermelon, cucumber, sunflower and other field or cover crops, particularly in the spring when the weather is dry. They sometimes cause stand loss. Okra growers are constantly battling fire ants because they are attracted to the oils in the plant. Where soybeans are planted flat rather than on raised beds or rows, tall fire ant mounds along the rows interfere with harvesting equipment. During dry periods, the fire ants sometimes chew irrigation tubing, as in vegetable crops.
Treatment options:
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Although fire ants are mostly a nuisance to field workers in these crops, their overall economic and ecological impact is unknown. In pecan orchards, fire ants prey on pests such as pecan weevils and hickory shuckworms; however, they can encourage aphids by preying on their natural enemies. The ants nest building aerates the soil of the orchard floor, which is beneficial, but they will feed on the meat of cracked pecans and can damage irrigation systems. Ant mounds may interfere with some types of harvesting operations. Chemical control is warranted only if the cost of control is less than the potential economic loss ants may cause. In pick-your-own operations, customer safety also should be considered.
Treatment options:
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A copy of the entire Imported Fire Ant Program Manual, which describes treatment programs for complying with the United States Department of Agriculture imported fire ant quarantine regulations, may be obtained from the Animal and Plant Health Inspection Service, Plant Protection and Quarantine, Domestic and Emergency Operations (4700 River Road Unit 134, Riverdale, Maryland 20737-1236).
Federal quarantine regulations mandate specific fire ant treatment(s) for plants to be shipped to areas free of fire ants, but each infested state may have additional regulations and agencies that enforce them. In Texas and Louisiana, for instance, laws mandate that plants must be apparently pest-free but do not mandate formal treatment programs. In addition to the products mentioned below, products containing abamectin (PT® 370 AscendTM), acephate (Orthene®), carbaryl (Sevin®), diazinon, pyriproxyfen (Distance®) and s-methoprene (ExtinguishTM) are registered for treating fire ants in turfgrass areas, around ornamental plants or in potting media. However, these are not approved quarantine treatments at this time. The following treatment suggestions are approved for commercially produced ornamental plants to be shipped out of a quarantined area (modified from Imported Fire Ants: A guide for Nursery Operators, Program Aid No. 1420, USDA, APHIS, December 1988). In all cases the producer must obtain a Compliance Agreement from the state regulatory agency (e.g., Texas or Louisiana Department of Agriculture, Arkansas State Plant Board, Alabama Department of Agriculture and Industries, Georgia Department of Agriculture). Greenhouse-grown plants may be exempt from quarantine treatment regulations if an inspector determines that the facility is tightly closed, but the grower still must have a Compliance Agreement.
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Treatment options
(For compliance with the USDA Fire Ant Quarantine):
Program 1: Fire ant-free nursery program for containerized nursery stock.
Program 2: Balled and burlapped stock.
Program 3: Field-grown woody ornamentals, preharvest.
Note: Nursery stock or plants must be shipped within a specific period of time following treatment, depending on the treatment applied.
Bodies of water such as rivers, streams, ponds and lakes are highly attractive to fire ants. Fire ant mounds around ponds and on dams and levees of fish farms can be a nuisance and pose a threat to workers. When using insecticides in these areas, every effort must be made to avoid contaminating water sources. Fire ant baits contain very small amounts of active ingredients and can be applied on shorelines close to water, but not directly in the water. To minimize the risk of runoff apply baits when ants are actively foraging so that ants collect the bait particles quickly. If individual mounds are treated use products with lower toxicity to fish, such as acephate (Orthene® TT&O). Pyrethrins and rotenone products are highly toxic to fish and should not be used. Do not apply any form of insecticide if rain is likely to occur soon after treatment. Nonchemical mound treatments with steam or very hot water may be suitable for sensitive areas.
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Fire ants invade bee hives and feed on developing bee larvae, occasionally destroying weak colonies. Use chemicals with care because the bees will be affected by insecticides.
Treatment options:

Certain forms of wildlife are especially affected by ants during and soon after birth or hatching. The risk is greatest during warm months. Fawns are vulnerable because they are born in June and because they instinctively remain motionless in their hiding places. Quail and ground-nesting waterfowl chicks are also attacked by fire ants. However, the effect of fire ants on wildlife populations over a large area has not been well documented. Fire ant control programs in wildlife areas are discouraged unless the benefits are clear and can be demonstrated. Many pesticides are toxic to wildlife (particularly to aquatic organisms) and may cause harm if not used properly.
Treatment options:
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Maintaining Native Ant Populations
The states infested with red imported fire ants have many native ant species, including several species of fire ants. Native ants often compete for resources with the red imported fire ant, attack mated fire ant queens trying to establish new colonies, and invade weakened fire ant colonies. Preserving and encouraging native ant species is considered the best defense against imported fire ants. If an area has fewer than 20 imported fire ant mounds per acre, insecticide bait products should not be broadcast because the fire ant problem is not severe enough to justify the destruction of other ant species.
ACKNOWLEDGMENTS
The authors are grateful to the thorough review comments from our colleagues, Dr. Jerry Cook, Dr. David H. Oi and Homer Collins.
For additional information about imported fire ant management contact your county Extension agent or visit these World Wide Web sites:
www. fireant.tamu.edu
www.uaex.edu/natural/fireant/firehome.htm
The information given herein is for educational purposes only. Reference to commercial
products or trade names is made with the understanding that no discrimination is intended
and no endorsement by the participating states Cooperative Extension Services is
implied.
| Ingredient | Trade name* | Use rate | Registered site(s) |
| abamectin
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PT370 Ascend
Clinch |
1 lb./acre or 5 to 7 Tbsps./mound (same as above) |
Turf, lawns, noncrop areas; indoor crevices or voids; utilities Citrus groves, barns, poultry houses |
| acephate
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Orthene Turf, Tree and Ornamental Spray (TT&O)
Pinpoint |
1 to 2 tsps./mound or 1 oz./5 gals./ 5 mounds to treat a 4-ft.-diameter circle |
Noncrop areas
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| 1 lb./100 gals. drenched into pots |
Container-grown nursery stock (Note: not approved as quarantine treatment) |
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| 2 tsps./mound | Turfgrass | ||
| bifenthrin | Talstar T&0 0.2 G, Flowable |
Varies with bulk density of potting media |
For use in fire ant quarantine program for fire ant-free nursery program |
| boric acid (Note: Scientific studies have yet to demonstrate the effectiveness of these products.) |
Bushwhacker Fire Ant Control
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3 lbs./acre
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Terrestrial food (vegetables, fruits, nuts, rangeland, pastures, forages) and nonfood (nursery, turf) crops, forestry areas, poultry farms |
| SafeCide | 1 to 2 lbs./100 sq. ft. or 1 to 2 cups/mound |
In poultry houses | |
| carbaryl | Sevin XLR Plus | 3 Tbsps./2 gals./mound | Pastures, rangeland, forested lands, |
| (other formulations | wastelands, nursery stock, vegetable | ||
| include 4F, 50W, | transplants (do not use on any food crop | ||
| 80S, SL, 5% and | not listed on the label), foliage plants, | ||
| 10% dust) | bedding plants (do not use in | ||
| greenhouses). Sevin 50W and 5% also | |||
| registered for poultry and premises, | |||
| although not specifically for control of | |||
| fire ants. | |||
| chlorpyrifos | Dursban | Varies with formulation | Read and follow label directions. |
| Lorsban 4E | 3/4 to 1 qt./acre in 25 | Citrus orchard floor | |
| or more gals. water | |||
| Lorsban 15G | At planting: 8 oz./ | Field corn, popcorn, sweet corn | |
| 1000 ft. of row | |||
| applied as a T-band | |||
| Lorsban 50W | 2 lbs./acre | Pecan orchard floor | |
| cyfluthrin | Countdown | 16 mls. per 1000 sq. | For control of crawling pests (including |
| ft., may vary with | ants) in and around livestock premises | ||
| type of surface | (including poultry houses) | ||
| dichlorvos | Vapona Concentrate | 1 gal./50 to100 gals. | Indoor livestock premises and poultry |
| Insecticide | houses |
| Ingredient | Trade name* | Use rate | Registered site(s) |
| fenoxycarb | Logic | 1 to 1.5 lbs./acre or | Horse farms and horse pastures, |
| 1 to 3 level tsps./ | nonbearing crops (apples, avocados, | ||
| mound | blueberries, citrus, nectarines, peaches, | ||
| pecans, plums), noncropped and | |||
| nongrazed areas on the farm, turfgrass | |||
| Award | (same as above) | Around container-grown ornamental and | |
| nonbearing nursery stock and on sod | |||
| farms; turfgrass areas | |||
| hydramethylnon | Amdro Insecticide | 1 to 1 1/2 lbs./acre | Turf, golf courses and grounds, parks, |
| Bait | or 5 Tbsps./mound | rangeland, pasture, noncropland | |
| Siege Fire Ant Bait | (same as above) | ||
| lambda- | Grenade ER | 0.2 to 0.4 fl. oz./gal. | In and around buildings housing |
| cyhalothrin | Premise Insecticide | livestock. For use as barrier and general | |
| surface treatment for ant control | |||
| imidacloprid | Goucho 480 | Seed treatment: | Sorghum |
| Flowable | 8 fl.oz./100 lbs. seed | ||
| permethrin | Y-Tex GardStar | 9 to 11.8 mls./gal./ | In and around livestock premises, |
| 750 to 1000 sq. ft. | including poultry houses, to control ants | ||
| or 5 to 10 mls./gal. | |||
| water/mound | |||
| pyrethrins | Organic Solutions | 4 Tbsps./gal./mound | Grasses; animal quarters; outdoor- and |
| All Crop Commercial | indoor-grown vegetable crops; | ||
| & Agricultural | ornamentals; herbs; spices; field grain | ||
| Multipurpose | crops; fruit, nut and vine crops | ||
| Insecticide | |||
| Pyrenone Crop Spray | 0.05 lbs./acre | Crops (for ant control) | |
| pyriproxyfen | Distance Fire Ant | 1 to 1 1/2 lbs./acre | Indoor and outdoor container- and field- |
| Bait | (0.35 to 0.5 oz./ | grown ornamentals (commercial | |
| 1000 sq. ft.) or | nurseries); ornamental tree farms; | ||
| 1 to 4 Tbsps./mound | nonbearing nut, citrus and other tree | ||
| fruits grown in nurseries; conifers; conifer | |||
| nurseries; sod farms; industrial sites; | |||
| uncultivated nonagricultural areas; | |||
| nongrazed pastures and rangeland (Note: | |||
| not approved as quarantine treatment) | |||
| rotenone | True Stop | 2/3 cup/gal.; | Vegetable and field crops, rangeland, |
| 8 to 10 fl. oz./ | sod farms | ||
| 4-in.-diameter mound | |||
| s-methoprene | Extinguish | 1 to 1.5 lbs./acre or | Turfgrass and landscapes, parks, zoos, |
| 3 to 5 Tbsp./ mound | golf courses, roadsides, airports, | ||
| to a perimeter of 4 ft. | cemeteries, perimeter areas of buildings, | ||
| homes, sheds, electrical and phone | |||
| boxes, pump houses and other associated | |||
| areas, forestry sites, commercial nurseries | |||
| including field-grown and container | |||
| stock, school grounds, sports fields, | |||
| pastures, rangeland, citrus groves, sod | |||
| farms, cropland (Note: not approved as | |||
| quarantine treatment) | |||
| tefluthrin | Fireban 1.5G | Varies with bulk density | For use in fire ant quarantine program |
| of potting media | for fire ant-free nursery program | ||
| terbufos | Counter 15G | At planting: 8 oz./ | In Texas, section 2(ee) for field corn, |
| 1000 ft. of row | popcorn, sweet corn and sorghum |
* All are registered® or trade markedTM product names.


Produced by Agricultural Communications, The Texas A&M University
System
Judy Winn, Editor
Michelle Mikeska, Graphic Designer
Educational programs of the Texas Agricultural Extension Service are open to all people without regard to race, color, sex, disability, religion, age or national origin.
Issued in furtherance of Cooperative Extension Work in Agriculture and Home Economics, Acts of Congress of May 8, 1914, as amended, and June 30, 1914, in cooperation with the United States Department of Agriculture. Chester P. Fehlis, Deputy Director, Texas Agricultural Extension Service, The Texas A&M University System.
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