Managing Fire Ants in Pastures

— Written By and last updated by Patricia Burch

Unfortunately, fire ants have found a home in most of our southeastern pastures. With the mild temperatures of spring and recent rains, they will be mounding up; so to speak, in the weeks to come. There are so many ways fire ants cause us problems, from damage to equipment, reduction in forage production, and of course possible pain and injury. Unfortunately, there is no simple solution to the fire ant problem. Management of these pests depends on the concentration of the mounds and locations. Of the products labeled for use in pastures, some are chemicals that treat the mound and will kill the ants, while others are insect growth regulators that can be broadcast across a pasture and will focus on making the queen of the colony sterile, eventually removing the colony.

What products can be used? Amdro Pro (hydramethylnon), Extinguish (methoprene), Extinguish Plus (methoprene+hydramethylnon), Esteem (pyriproxyfen), Award (fenoxycarb) Logic (fenoxycarb), Sevin 80WSP, XLR Plus, and SL (carbaryl). Some of these products are recommended for mound treatment, some for broadcast, some both. Sevin is specifically used as a drench treatment. Some of the products are insect growth regulators (IGRs) that will cause the queen to become sterile, causing reproduction to cease and thus controlling the colony. IGRs are methoprene, pyriproxyfen, and fenoxycarb.

Timing and proper product application is the key to treating for fire ants. The best time to treat is mid-spring and fall, and mid-morning when air temperatures are around 70 degrees F. It is also important to NOT treat if the ground is wet, or if rain is expected within the next 36 hours. Once the bait gets wet, the ants won’t be interested in taking it into the mound. You can check for ant activity or “foraging” by placing potato chips or cheese puffs on the ground near the mound. If ants appear on the snacks within 30 minutes, then the colony is active and foraging.

Some other key tips to remember:

  • Do not store products past the expiration date. They will lose attractiveness to the ants and become ineffective.
  • Do not store near other pesticides or fuels. They may absorb odors and affect taste for the ants, becoming ineffective.
  • Do not apply directly on mounds. Ants do not travel on the top of the mound.
  • Do not disturb the mound when treating. This will upset the ants and disrupt their normal foraging behavior.
  • Do not re-apply baits within ten days of applying a direct poison, as there will be no ant activity during this time.
  • Always apply and re-apply when needed, as suggested on the label.

For more information or a copy of fire ant management extension publications, contact the N.C. Cooperative Extension, Sampson County Center at 910-592-7161, or visit the following article:

Extension Factsheet attach_file

Red Imported Fire Ant in North Carolina

This publication discusses the biology and spread of fire ants and the various methods that can be used to control these ants.

The use of brand names and any mention or listing of commercial products or services in this article does not imply endorsement by North Carolina State University nor discrimination against similar products or services not mentioned.