Tawny Crazy Ants | Vol. 3, No. 23

Nylanderia fulva

Order: Hymenoptera
Family: Formicidae

“There are so many of these ants that when we spray around the outside of the house to kill them, their bodies pile up in mats and then other ants can walk across without getting in the spray!”

For the past nine years, residents of the Mississippi Gulf Coast have been dealing with a new invasive ant that builds to extremely high populations during the summer and fall, making outdoor activities less enjoyable and frequently causing malfunctions in electrical equipment. Tawny crazy ants were first detected in the state in 2009, after being detected in Texas in 2002. Fortunately, tawny crazy ants are still restricted to the three coastal counties of Mississippi, but because colonies can easily be transported in potted plants, mulch, and similar materials, it is likely they will spread farther north, as they have in Texas.

Although they do not sting, tawny crazy ants are a significant and costly nuisance for residents of infested landscapes. For one thing, it’s difficult to enjoy being outside in the lawn or patio when you have dozens of ants crawling up your legs. Even more vexing, these ants often cause electrical problems because of accumulations of dead crazy ants inside equipment. Owners of infested landscapes usually have a long list of costly electrical problems crazy ants have caused, including failed air conditioners and water well pumps, shorts in light switches, and automotive problems. One homeowner reported having four service repairs to their air conditioning system within a twelve month period because of tawny crazy ants.

Control: Tawny crazy ants are extremely difficult to eliminate from a landscape once they are established. There are cultural practices and treatments that can help keep populations to reasonably tolerable levels in and around buildings, but it takes a considerable amount of effort and expense to achieve and maintain this level of suppression. To achieve optimum control it is usually best to work with a professional pest control company that has experience with tawny crazy ants. Some of the most effective treatments can only be applied by pest control companies. See “Tawny Crazy Ant Control Recommendations” for more detailed information.

Ant Identification: Think you might have tawny crazy ants but live farther north in the state? You may have Argentine ants instead. The only way to know for sure is to mail in some ants for identification. Although their numbers rarely reach the levels of tawny crazy ants, Argentine ants also occur in large numbers, and they have been here longer and occur farther north, with overall behavior and effects that are similar to tawny crazy ants. Control is also similar. To submit a sample for identification, preserve ants in alcohol or vinegar in a leak-proof bottle and mail to: Extension Insect ID, Box 9775, Mississippi State, MS 39762-9775.

Blake Layton, Extension Entomology Specialist, Mississippi State University Extension Service.

The information given here is for educational purposes only.  Always read and follow current label directions. Specific commercial products are mentioned as examples only and reference to specific products or trade names is made with the understanding that no discrimination is intended to other products that may also be suitable and appropriately labeled.

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