Ornamental & Turf Insect Note Logo


Steve Bambara & Wes Watson, Extension Entomologists

CAUTION: This information was developed for North Carolina and may not apply to other areas.

FIRE ANT, Solenopsis invicta, Formicidae, HYMENOPTERA

General Information

Fire ants have established themselves across much of North Carolina, which includes the major areas of horse operations.  These ants require access to sunshine and open land and have become very successful in this habitat. However, their presence in a pasture may impact horse operations in many ways.  Impact may be felt through:

  • Lost Labor
  • Animal Injury
  • Equipment Damage/Wear
  • Hay Production
  • Medical/Veterinary Costs
  • Forage Degradation
  • Electrical Equipment Damage
  • Infested Feed
  • Reduced Feeding
  • Foal endangerment
angus in pasture


There is no single simple solution for managing fire ants on a farm.  Management depends upon the number of mounds and locations. There are numerous fire ant pesticides, however, only a few are labeled for use directly in the pasture.  Some chemicals are for directly treating a mound, and some are baits containing insect growth regulators (IGRs) that may be broadcast across the pasture.  There are no effective sprays.  In addition, it may be helpful or necessary to control fire ants in adjacent areas outside the pasture with different products.   Fire ants may also infest barns or paddocks and create additional problems to horses and caretakers.

Direct mound drenches
  Fast acting
  Insecticides applied only to targeted mounds
  More expensive for large areas
  More labor intensive
  Treatments affect only colonies with visible mounds
Broadcast bait treatments
  Quick and easy application
  Less hazardous, generally
  Least expensive method for large areas
  Less labor required
  Slower than liquids (too slow for immediate control)
  May harm helpful non-target ants

"What can I use in grazed pasture?"
hydramethylnon (Amdro Pro) For mound or broadcast; Consult label for restrictions and directions in using this bait in pasture.
hydramethylnon (Amdro) For mounds in horse pasture only where horses are not used for human consumption and in nonpasture farm areas.
methoprene (Extinguish) For mound or broadcast, no withdrawal period.  Insect growth regulator affecting brood. 
methoprene + hydramethylnon (Extinguish Plus) For mound or broadcast.
pyriproxyfen (Esteem Ant Bait) For mound or broadcast on grass pasture.  Slower working bait that kills developing brood rather than workers. Spring or Summer application recommended. (may be combined with Amdro)
fenoxycarb (Award Fire Ant Bait) For mounds in horse pasture only where horses are not used for human consumption and in nonpasture farm areas.  Slower working bait that kills developing brood rather than workers.

carbaryl (Sevin SL) for mound drench only; follow label directions; may be foraged after application has dried. Best when applied in morning when air temperature is about 70o F.


Do not apply baits and drench at the same time.  Allow 10-14 days between the two applications. Ants will not forage and accept bait while they are disrupted by poison. The best months to treat are mid-Spring and Fall.  The best time of day to treat is mid-morning when air temperatures are around 70 degrees F.  To check if fire ants are active, place a few potato chips or puffed cheese snack on the ground.  If ants are noticed within 30 minutes, then colonies are active and foraging.
For bait broadcast treatment, based on two Alabama Extension studies by Henry Dorough, an effective application strategy is to use a 50/50 bait mix of hydromethylnon (AmdroPro) and methoprene (Extinguish).  Apply in a skip-swath pattern in a pasture.  This can save 50% on material applied and was just as effective as complete coverage.

"What can I use to treat areas outside of the pasture?"

For a list of the products available for treating fire ants in pens, corrals, barns and outside of pastures, nongrazed pasture and rangeland, consult the Agricultural Chemicals Manual. Included in the list may be Award, Distance, Suspend SC, Clinch.  Consult each label for specific limitations of where and how these products may be used.

Nongrazed Areas

Treating Inside Barns and Paddocks

Special Tips for Using Baits !  Do's and Don'ts    ( Most bait failures are attributed to application error. )

  1. Check for ant activity using potato chip test first.
  2. Do not apply if ground is wet or rain occurs within 36 hours.
  3. Do not store open product for longer than package allows.  Some baits have a short shelf life and are not attractive when carrier is stale.
  4. Do not store baits near other pesticides or fuels from which they may absorb odors and taste.
  5. Do not apply baits directly on mounds, fire ants do not come and go from the top of the mound.
  6. Do not disturb mounds when using baits so as not to interfere with normal foraging patterns, no matter how much fun it is.
  7. Do not apply within ten days of applying a direct poison as there will be limited or no foraging.
  8. Reapply as suggested by the label.  This is not a permanent solution.

North Carolina Fire Ant Quarantine

Movement of Hay and other commodities outside of the red area are regulated by the
NC Department of Agriculture and Consumer Services and require a permit.

Helpful References and Resources

Published by North Carolina Cooperative Extension Service

Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University at Raleigh, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by the North Carolina Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage and examine a current product label before applying any chemical.
© 2008 NC Cooperative Extension Service

Prepared by: S. B. Bambara & Wes Watson, Extension Entomologists. Ant image by Rebecca Norris, USDA APHIS forestryimages.org . Spreader photo from Texas Agr. Extension Service, Horse and mound image by S. Bambara. Thanks, to M. Waldvogel and Kathy Flanders.

ENT/for-05 September, 2008
Web page last reviewed January, 2011 by the webperson.