Invasive Ants Cover Most of Louisiana

By Dr. Dennis Ring, LSU AgCenter Entomologist

BATON ROUGE -- The section 18 quarantine exemption use label for Termidor SC insecticide to be used in management of tawny crazy ants in Louisiana has been renewed.  This exemption was authorized on April 1, 2016 and will expire April 1, 2019.  The following parishes are included in the exemption:  Ascension, Beauregard, Calcasieu, East Baton Rouge, Iberia, Iberville, Jefferson, Lafayette, Lafourche, Livingston, Morehouse, Orleans, Rapides, St. Bernard, St. Charles, St. Landry, St. Martin, St. Mary, St. Tammany, Tangipahoa, Terrebonne, Vermilion, Vernon, Washington, and West Baton Rouge.  See information below on this insect.

A new invasive pest ant was discovered near Pasadena, Texas in 2002 by Tom Rasberry, a pest management professional.  This ant was called the Rasberry crazy ant after its discoverer.  It is also called the Tawny crazy ant (official common name), hairy crazy ant, and Caribbean crazy ant.  The scientific name is Nylanderia fulva.   Crazy ants get their name because they crawl around like crazy.  It is fairly easy to identify an ant as a crazy ant because of this behavior.  However, there is more than one species of crazy ant, and it is very difficult to distinguish tawny crazy ant from other crazy ants. 

The numbers of these ants build up to very high levels, and the ant may become a great nuisance.  In some cases the numbers of tawny crazy ants are so high that people cannot enjoy their yards and pets avoid the yard.  Wildlife may also be affected as the ants cover the landscape and displace other organisms.  These ants do not have stingers and thus, do not sting.  These ants do bite causing a sharp pain that fades quickly.  Tawny crazy ants also get in electrical equipment resulting in short circuits and electrical equipment failure.  The economic impact and impact on wildlife of these ants are currently unknown.  Very high numbers of ants may cover the ground and trees resulting in the movement of wildlife out of the area.  This ant has been observed in bee hives causing the bees to leave quickly.  The tawny crazy ant has been observed to displace fire ants.  However, residents that have experienced tawny crazy ants prefer fire ants.

Adult tawny crazy ants are reddish-brown in color. Workers are all about the same size, 1/8 inch long, have long antennae and legs and have many, long, coarse hairs on their body. There is no club on the 12 segmented antennae.  These ants are found in very high numbers (millions) and crawl erratically and rapidly.  These ants do not make a centralized nest, and nests may occur under anything that holds moisture.  Pictures and videos of these ants may be found at the following website:  http://urbanentomology.tamu.edu/ants/exotic_tx.cfm.

Most ant baits are not attractive to these ants and thus, not effective.  However, they have been observed picking up Max Force® ant bait (use the fine granule, hydramethylnon or fipronil) and Whitmire Advance Carpenter Ant Bait.  Whitmire Advance Carpenter Ant Bait (abamectin) may be ground into smaller particles so that it can be more easily taken by the crazy ants. It is important that you use fresh bait and apply it when the ground is dry and no rain is expected for 24 hours. Broadcast bait over the entire infested area.  Baits alone are inadequate to reduce high densities of these ants but may be effective against these ants when densities are low in the spring.

Areas around structures may be sprayed using acephate, pyrethroids, fipronil, and dinotefuran (Alpine) to form buffer zones.  Tawny crazy ants will cross these buffer zones in 2 to 3 months after treatment.  When dead ants build up in piles, the piles must be removed to treat the area under the dead ant piles.

Louisiana received a Section 18 quarantine exemption use label for Termidor SC insecticide to be used in management of tawny crazy ants.  A Termidor SC (0.06%) treatment may be applied 3 ft up the side of structure and 10 ft out from the foundation. Also applications may be made to a 10 ft. radius around electrical equipment to help protect the equipment from shorting out.  In parishes not listed on the special label, applications of Termidor SC may be made within 1 foot of the foundation.  Impervious surfaces such as concrete may not be treated using Termidor.  An application may be made to the joint between the slab and concrete.  The joint would be treated using a pinstream of insecticide or a flat fan spray pattern applied sideways.  Alpine may be applied to impervious surfaces.  Termidor treatments can be applied only 2 times per year per structure and must be done at least 60 days apart.

It is extremely important not to treat impervious surfaces with Termidor to prevent this product from being introduced in aquatic systems.  Fipronil (active ingredient of Termidor and other products) is toxic to some aquatic organisms (ex. water flea) in very small amounts.  Fipronil is also a very important chemical in managing subterranean termites.  It is very undesirable that this chemical lose its label becoming unavailable for subterranean termites and other insects because it was found in aquatic systems.  Samples are being taken in aquatic systems of Louisiana looking for Fipronil and other insecticides.

The tawny crazy ant must be specifically identified from a parish before Termidor can be used for the tawny crazy ant.  Tawny crazy ants must be identified by an LSU AgCenter entomologist. Samples have to be sent to the AgCenter and identified before any treatment under the Section 18 quarantine exemption may be applied in a parish.  Samples can be sent to Dennis Ring at 404 Life Sciences Bldg., Department of entomology, 110 LSU Union Square, Baton Rouge, LA 70803.

The emergency label states that Termidor SC can be applied for control of crazy ant species associated with man-made structures in Louisiana within parishes from which tawny crazy ants have been identified by LSU AgCenter entomologists as well as additional parishes when positive identification has been made by LSU AgCenter entomologists.

For the remainder of the areas in the landscape, another product, TopChoice™ Insecticide (0.0143% fipronil) granules can be broadcast at a rate of 87 lbs per acre or 2 lbs per 1,000 sq ft as instructed for red imported fire ant and nuisance ant control. Treated turf should be watered in after application. Only one application per year is allowed. Do not apply within 15 ft. of fresh water or 60 ft of estuarine bodies of water.

Disrupt the foraging of these ants into trees and houses and suppress ants in visible nests. Use a pyrethroid or an organophosphate applied around trees approximately two feet up and one foot out from the base of trees.  Treat all surfaces of the bark, and treat all the trees on your property at the same time. If possible, drench any nests of crazy ants seen with contact insecticides. 

Remove anything that these ants may nest under or in.  Do not discard infested materials in non-infested areas.  Remove obstacles that would prevent a thorough uniform spray application. 

When dead ants accumulate, carefully remove them with a leaf blower outdoors or vacuum indoors; i.e. do not disturb or remove the insecticide from the treated surfaces. Do not vigorously wipe or scrape clean treated surfaces.

The ants spread naturally through budding.  However, they are moved much more rapidly through the actions of humans.  They may be moved in any material or container that is infested.  It is extremely important that these ants are not moved into new areas.  Carefully inspect incoming materials to make sure these ants are not introduced.