By Chris Hicks, County Director – UT Extension Smith County
I had a number of calls in 2020 regarding fire ants, and those calls have continued into 2021. Some of these calls have turned out to be false alarms, while others have indeed been fire ant mounds. If you suspect you may have fire ants on your property, I hope to give you some tips on making a positive ID.
First, what is a fire ant? Fire ants are non-native ants that get their name from their sting which causes burning and sometimes blistering. There are 3 types of imported fire ants: red, black, and hybrid. Within a colony, their sizes range from 1/8” to 1/4” in length, and like other ants, you can find winged males and females in the nest.
The 3 types of fire ants share common characteristics such as a ten-segmented antenna with a two-segmented club and a two-segmented waist. Of course, seeing these characteristics requires a microscope, and putting them under a microscope requires catching them. Identifying them without getting stung is obviously the goal.
Dr. Karen Vail, UT Extension Urban Entomologist, suggests that to decrease the chances of being bitten and stung by fire ants, place a small index card with a food item (honey, peanut butter, cookies, etc.) next to the mound but not on it when temps are between 70F and 90F. As soon as ants start feeding, grab the index card by the corner and place it in a Ziploc bag, seal the bag, and place in the freezer. You could also use an aspirator to put the ants in a vial of alcohol if you prefer not to have ants in your freezer.
Besides collecting a specimen, the aggressive nature of fire ants in comparison with other ant species is another characteristic to look for. Generally, hundreds of fire ant workers will swarm out of the ant mound when disturbed and run up vertical surfaces to sting, unlike other species which tend to run horizontally to try and get away. Again, be cautious when using this method so that you avoid being stung.
A final clue, but not a foolproof method of ID, is to look at the size and shape of the mound. Imported fire ants build mounds in almost any type of soil but prefer open, sunny areas such as pastures, parks, lawns, meadows, and cultivated fields. Mounds can reach 18 to 24 inches in height and do not have an opening in the center. Allegheny mound ant mounds are often confused with fire ant mounds as they can be even larger and also lack a central opening.
If you suspect you may have fire ants on your property, safely collect some samples, make sure they are frozen or have been killed with alcohol, and bring them to the UT Extension office at 125 Gordonsville Highway in Carthage for positive identification. Also, fireants.utk.edu has excellent information regarding identification and management of fire ants.
