Categorized | Agriculture

UH scientists share tips on how to identify, control little fire ants


Little fire ants, first found on O‘ahu about six months ago, are continuing to spread throughout the island. The ants are already well established on the Big Island and have been found but were controlled on Kaua‘i and Maui. Faculty and staff at the UHM’s College of Tropical Agriculture and Human Resources and the Hawai‘i Department of Agriculture have tips for identifying and controlling these invasive and damaging pests.

Little fire ant (LFA), Wasmannia auropunctata, is a serious pest because this tiny ant can easily spread undetected into yards and homes, parks, landscapes, vacant properties and forests. LFA deliver a very painful sting (similar to an electric shock) to people, pets, livestock, and even marine wildlife such as sea turtles and ground-nesting birds. LFA are attracted to eye fluids and typically sting near animals’ eyes, which can lead to blindness due to clouding of the cornea, or keratopathy.

What can you do? Here are the steps for basic detection and control:


— Areas where LFA are commonly found:

– Trees and shrubs, especially any fork at the base of trunk, in crotches of branches, and under moss growing on trees or shrubs

– Flowers, in the stamen and pistil

– Edges of building foundations and concrete slabs

– Cracks in concrete

– Electrical outlets

– Fallen logs and piles of plant debris

– Under potted plants

– Dumpsters, trash cans, rubbish piles

– Stockpiles of seldom-used flower pots, lumber, hollow tiles, rocks etc.

(Modified from C. Vanderwoude, 2008,“General Emergency Response Plan for Invasive Ant Incursions in the Pacific”


— Use peanut butter as an attractant for detection. Check for ants by smearing a thin layer of peanut butter on one end of a chopstick or any wooden or plastic stake. Place stake on the ground every 10–12 paces, including in potted plants and at the base and in branch crotches of trees. The best times are in the morning or on overcast days, avoiding heavy rain or mid-day sun and heat. After about 40 to 45 minutes, check for LFA on the stake.

– Are the ants red-orange, slow moving, and less than 1/16” long (thickness of a penny)?

– If YES, they are probably LFA. Place the chopstick with ants into a zip-top bag and place it in the freezer for at least 24 hours to kill the ants.

– If NO, repeat monitoring with peanut butter every month.

— Identify and verify that they are little fire ants in order to use appropriate control measures. Bring bagged ant samples to the following locations for confirmation:

– O‘ahu: Hawai‘i Department of Agriculture

Plant Pest Control Branch

1428 South King Street, Honolulu, HI 96814

– Big Island: UH-CTAHR Komohana Research and Extension Center

875 Komohana St. Hilo, HI


Hawai‘i Department of Agriculture

16 East Lanikaula St., Hilo, HI.


— Treat with ant bait insecticide. Ant food bait mixed with a slow-acting insecticide is the only effective way to kill and eliminate an LFA colony, because it allows the worker ants to carry the poison to the queen(s).

– WHAT TO USE: Only use bait insecticides that are specifically labelled for indoor and/or outdoor use by broadcast application or in bait stations, or in self-contained bait stations for indoor (see LITTLE FIRE ANT PRODUCTS AVAILABLE FOR HOMEOWNER USE for a list of baits that are attractive to LFA, available at Komohana Research & Extension Center).


Extinguish Plus (also for outdoors) 2724-496

Hot Shot MaxAttrax Ant Bait 29688-214-8845

Maxforce Complete (also for outdoors) 432-1255

Raid Ant Bait III 4822-529

Raid Double Control Ant Baits II (for

potted plants) 4822-472

Tango (also for outdoors) (bait must be 2724-420

formulated – see


Advance 375A499-370

Advion Fire Ant Bait 100-1481

Amdro Ant Block 73342-2

Amdro Fire Ant Bait 73342-1

Amdro FireStrike Yard Treatment 73342-6

Distance Fire Ant Bait 1021-1728-59639

Esteem Ant Bait (fruits, nuts, vegetables) 59639-114

Extinguish Plus (also for outdoors) 2724-496

Maxforce Complete (also for outdoors) 432-1255

Siesta Insecticide Fire Ant Bait 7969-232

Tango (also for indoors) (bait must be 2724-420

formulated – see

– Read and follow all label directions – some products can be used near food crops (fruit trees, vegetable gardens, etc.), while others cannot. “Rotate” or use different bait products to avoid “shyness,” when ants stop taking the bait. Some insecticides act as insect growth regulators, which affect the queens’ ability to reproduce and prevent eggs and larvae from maturing – these effects take longer to be noticed.

– WHEN TO USE: Ants tend to forage when it’s cool and dry. The active ingredients in ant baits are often deactivated by UV light and humidity (including rain and watering), which make them environmentally friendly but require reapplications every 2-4 weeks. It is best to apply baits early in the morning or at dusk, avoiding rain. Do not water before or after bait applications. Read and follow all label directions for safety.


— Check, treat, recheck, repeat. It may take several reapplications of bait over a 6- to 12-month period to kill a little fire ant colony. Recheck with peanut butter regularly and treat with insecticidal bait when necessary. It is critical that infested plants, building materials, trash, etc. be treated on-site and not moved or dumped, which will further spread the ants.

Free publications about little fire ants, including “Little Fire Ant Products Available for Homeowner Use,” are available online at (click on first publication), or at UH-CTAHR’s Extension Office at 875 Komohana Street in Hilo or by calling (808) 981-5199.

One Response to “UH scientists share tips on how to identify, control little fire ants”

  1. Carol Noel says:

    There is no mention of Avaunt nor Provaunt…. is it no longer recommended in the battle against LRFA? Is there nothing, yet, effective for use as a repellent?



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