By Carl J. Boxberger, EMGV
Fire ants are a serious nuisance pest in home lawns. They form unsightly mounds in sunny areas in lawns or next to sidewalks and driveways where soil temperatures are greater.
When their mounds are disrupted, their bites and stings can cause pain and serious injury to people or pets they land on.
Description and Biology
Red fire ants are about a quarter-inch long, red-brown, with shiny black abdomens. They are native to South America and, having escaped their natural enemies, thrive in our southern landscapes.
There are three types of adults in a fire ant colony: winged males, reproductive females and worker ants. Queen fire ants can lay 800 or more eggs per day. Worker ants are sterile females, wingless and protect the colony by feeding the queen, defending the nest, and foraging for food.
As the ant population grows new mounds will pop up to support the growing population. Also, if a mound is disturbed, the queen will be moved and a new mound will surface.
Control
Drenching the mound with greater than two gallons of hot water or mechanical disruption of the mound can reduce fire ant activity, however, fire ants will form new mounds a few feet from the original mound. Do not pour gasoline, diesel fuel, ammonia or chlorine on the mounds as these are dangerous and will contaminate the soil and ground water.
Broadcast pesticides applied over the entire lawn will only control ants on the surface and will not kill the colony deeper in the soil. It may kill beneficial insects as well.
Individual mound treatment is probably the best option for home lawns. Commercially purchased baits should not be placed on top of the mound but placed within a two-foot radius around the mound. The ants will take this bait into the mound and feed the queen and kill the colony.
As with all pesticides read and carefully follow all label directions.
Conclusion
Nest building by fire ants, like common ants, will reduce soil compaction and help aerate the soil. Fire ant diet includes other arthropods including insects, ticks and mites. So, fire ants can be beneficial to the environment.
Today, there are five times more ants per acre in the United States than in their native South America.
Resources
NCSU Turf Files – Fire Ants in Commercial Turfgrass, Home Lawns and Landscapes by Dr. Terri Billeisen , Extension Associate, Entomology and Plant Pathology – NCSU
Center for Disease Control: https://www.cdc.gov/niosh/topics/insects/fireants.html
Medical problems and treatment considerations: http://fireant.tamu.edu/files/2011/12/FAPFS023_2002rev_Medical.pdf
OSHA Factsheet: https://www.osha.gov/OshDoc/data_Hurricane_Facts/fire_ants.pdf