Fire Ant Management In Pastures

By John Dorner

General Information

Fire ants have established themselves across the southern half of North Carolina.  Their requirement of access to sunshine and open land have made pastures an excellent habitat for them. However, their presence in a pasture impacts livestock operations in many possible ways.  Impact may be felt through:

• Lost Labor
• Animal Injury
• Equipment Damage/Wear
• Hay Production
• Medical/Veternary Costs
• Forage Degradation
• Electrical Equipment Damage
• Infested Feed
• Reduced Feeding

Management

There is no single simple solution to 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 to control fire ants in adjacent areas outside the pasture with different products.

Direct mound drenches have advantages and disadvantages to balance.

    Advantages-

•  Fast acting
•  Insecticides applied only to targeted mounds

 Disadvantages-

•  More expensive for large areas
•  More labor intensive
• Treatments affect only older colonies showing visible mounds

Broadcast bait treatments also have advantages and disadvantages.

    Advantages-

•  Quick and easy application
•  Less hazardous, generally
•  Least expensive method for large areas
•  Less labor required

 Disadvantages

•  Slower than liquids (too slow for situations where stings are a major concern)
•  May affect helpful non-target ants

“What can I use in grazed pasture?”
BAITS hydramethylnon (Amdro Pro or Siege Pro) for mound or broadcast; Consult label for restrictions and directions in using this bait in pasture. methoprene (Extinguish) for mound or broadcast methoprene + hydramethylnon (Extinguish Plus for mound or broadcast pyriproxyfen (Esteem)

for mound or broadcast on grass pasture

(may be combined with Amdro)

fenoxycarb (Award) for mounds in horse pasture only where horses are not used for human consumption. Nonpasture farm areas. spynosad (Justice) permanent pastureland, corrals and around animal facilities.  (May not be available in stores.)

DRENCHES carbaryl (Sevin) 80WSP, XLR Plus, SL 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 in the 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, colonies are active.

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. Treated Untreated  Treated Untreated  Treated Untreated  Treated

Skip-Swath pattern for Fire Ant Bait application

Treating Areas Outside of Pastures

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, Clinch.  Consult each label for specific limitations of where and how these products may be used.

NC 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.

Source:ncsu.edu