Fighting the Invasion of the Fire Ants

It’s a red, aspirin-size invertebrate with a bad attitude, and it’s coming soon to a yard near you.

And if you think a wee bug can’t inflict enough pain and irritation to keep you from playing in the grass barefoot or gardening without gloves, think again.

Red imported fire ants, Solenopsis invicta, have arrived in Orange, Los Angeles, San Diego, San Bernardino and Riverside counties as recently as fall.

Experts believe they may have been accidentally brought in via potted plants to local nurseries and then circulated into housing developments. Nasty little insects whose native homeland is South America, these ants have had the biological good fortune to have few, if any, natural enemies in the northern hemisphere, and their powers of survival and expansion are impressive.

To the uninitiated, imported fire ants are the enemy. They kill native ants and swarm the eyes, nose, mouths and throats of newborn ground-nesting wildlife like quail, deer and rabbits, injecting their burning poison and inflicting unimaginable misery.

They make it impossible for children to play unfettered in backyards, and camping in fire ant country is tolerated by only the hardy few.

The only upside of fire ants is really a strange twist of fate. In killing native insects they inadvertently destroy insects that homeowners and farmers alike consider pests, bugs like flea larvae, chinch bugs, cockroach eggs and boll weevils. Still, I’d take fleas over fire ants any day.

Fire ant mounds can pop up anywhere, although you’re most likely to find them in well-irrigated places like lawns, flower beds, vegetable gardens and at the bases of trees.

Typically their mounds don’t get any higher than a foot and a half, but they may also be nearly flat, particularly during dry spells.

The soil of a fire ant mound looks slightly sifted and grows in size after it rains as the ants raise the mounds to keep their eggs and larvae away from the water zone. This is also when mated queens leave home to begin building new colonies.

The danger to kids and ground-nesting birds is part of the reason experts like Bart Drees, coordinator for Texas’ fire ant management program, said, “Our best offense is education. Learn what a mound looks like and show them to your kids.”

But you’ll need to do more than that if you want to keep your property fire ant free. You’ll need to be vigilant about inspecting for the ants and, according to Drees, use a two-step approach.

The first step is to apply a bait insecticide over your property twice a year--in the fall and spring when the ants are most active.

You can choose between using a growth regulator that renders queen ants sterile and unable to produce more workers, or bait that kills the ants.

Both are slow-acting, so don’t expect to see results for several weeks after spreading. Apply the bait when the ground is dry and rain isn’t expected for at least 24 hours.

The second step is to treat mounds with an insecticide labeled for use on ants. Treat only the most dangerous mounds, those that are in high-traffic areas or are particularly threatening. Other mounds will be eliminated more slowly via step one. Fire ant experts at the Texas Agricultural Extension Service recommend you wait at least three days after the first step to begin the second.

Because the ants are so new to California and pesticides are heavily regulated here, products currently available in other states may take time to show up on the shelves.

If you dislike using any poisons on your property, a more organic treatment is simply to boil water--about three gallons--and pour it onto individual mounds.

With a 60% success rate, this method was widely regarded as the best organic fire ant control for years until gardeners realized the boiling water killed the grass and plants it touched, and made the soil as sterile as pesticides did.

Fire ants are aggressive, and even a single ant can cause you no end of grief if it stings you.

Where the ant injects its poison into your skin, a small blister will appear in a few hours, although the wound will itch and burn immediately.

If you’re not sure what stung you, you’ll know it’s a fire ant in a few days when the blister forms a white pustule, and the sting area is still itching. If you find a fire ant mound either on your property or at a public place, call the California Department of Food and Agriculture’s toll-free pest response hotline at (800) 491-1899 to report its existence.

To see some slick pictures of fire ants and their mounds, visit Texas A&M; University’s entomology department Web site at https://entowww.tamu.edu/extension.