Red fire ants on the march in Southland
IT’S August and rising mercury is sure to bring ants crawling into the house. If you’re lucky, they’ll be Argentines snaking across the kitchen counters and bathroom floor. California hosts the world’s largest colony of them, and it runs the length of the state. So get out the spray and count your blessings, something far more sinister is coming down the pest pike: Solenopsis invicta, or RIFA, for short.
Also native to Argentina, red imported fire ants swarm and can sting more than once -- and can even sting in synchronized groups. Squash the one you just found on your arm, and the signal goes out for all others that are crawling up your body to attack. The stings cause painful pustules that can last for days.
“They change the ecology of an area,” says John Kabashima, an Orange County based entomologist with the UC Cooperative Extension and a RIFA expert. “They’re aggressive foragers, and they’ll kill anything that can’t get away from them.”
There have been two cases of elderly bedridden patients stung to death by the fire ants in the Southern U.S. Cattle in Texas have suffocated from stings swelling their air passages shut.
According to Kabashima, the insects enter houses “looking for oil -- in clothing, oils on jackets, in the kitchen, in dog food. They get into homes a lot, and they love irrigated yards and swimming pools for water.” They have thrived in the southern United States since first arriving from their native Brazil and Argentina in the early 20th century, with its summer humidity and heat providing the perfect tropical conditions for their mating and empire building.
In Southern California, where they first appeared in Los Angeles and Orange County in nursery shipments from Texas in 1998, they flourish in an irrigated paradise of gardens and farms. Orange County is currently under quarantine for them, as is the Coachella Valley.
“The Coachella Valley is just inundated with RIFA,” Kabashima says. “It’s an artificial paradise for fire ants, they have wall-to-wall golf courses, it’s humid all day. They couldn’t exist in the desert. They’re a tropical insect. There are none active in the natural areas.”
So far only 8.6 miles of Los Angeles County, in Cerritos and Azusa near the Orange County border, is under quarantine. Unfortunately, state funding for all local eradication programs was lost in October 2003.
At that time L.A. County had identified 736 RIFA-infested sites, 93 of which are still active and being treated. These included such far-flung areas as Sylmar, Chatsworth and the San Gabriel Valley. A more extensive list of affected communities in Los Angeles County can be found at: https://acwm.co.la.ca.us/scripts/RIFA.htm.
The halt in eradication programs during times when financially strapped counties scrambled for funding helped the fire ants gain ground. Before the funding loss, Kabashima says, “national experts thought we might have a chance.... They thought we might be the first invaded state to eradicate them.” Orange County voters recently agreed to pay $5.42 per household annually to restart eradication efforts, and voters in the Coachella Valley, where there are public parks with 100-yard-long RIFA mounds, passed a ballot measure this spring in which households will be assessed a modest fee for eradication efforts.
“We were performing eradication before,” says Richard Iizuka, director of Los Angeles County’s Environmental Protection Bureau, “and now we’re leaving it up to the homeowners.”
Until the most recent state budgets determined there would be no funding to fight the ants, Iizuka says L. A. County had been “in a holding pattern.” Now they’re “considering a variety of different approaches that could include ballot measures such as those in Orange County.”
Meanwhile, homeowners who think they’ve got the ants can do the potato chip test. The insects are drawn to the oily snack and will soon be swarming one set out near a suspected nest. They are small and dark red, nearly black, just like Argentine ants, but they sting and their nests have mounded entrances.
L.A. County homeowners who think they have an infestation are encouraged to report it to the California Department of Food and Agriculture hotline: (888) 434-7326.
Spraying won’t get rid of them. Survivors will pack up the remaining queens -- there are multiples in a colony -- and get started elsewhere. Straight poison baits won’t work either, since queens don’t take food directly.
The most effective dispatch method is what Kabashima calls the “Texas two-step”: First a bait of soybean oil, corncob and growth inhibitor to sterilize the queens is set out for RIFA workers to carry back to the nest. Within a few days the queens are sterile and a second bait of poison is put out to kill the workers.
Californians can still hold hope of erasing fire ants from the state. In Texas, where RIFA have been declared established, bio controls are being used to depress their populations. Phorid flies, an enemy brought in from Argentina, lay their eggs on the ant’s body and the hatchlings then kill the ant. Their mission is accomplished when the ant’s head falls off. A satisfying sight, no doubt, to anyone ever stung by one.
While counties scrape together eradication funding, Kabashima says local governments are struggling to keep the awareness up.
“Homeowners needn’t panic yet,” he says, “but if the opportunity to fund an assessment comes on the ballot, vote for it, otherwise they will get out of hand, and homeowners will be responsible to fight a losing battle. Then it will be time to panic.”
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Spraying’s only the beginning
Argentines come indoors in the winter for warmth and dry ground when rain floods them out of their shallow nests, summer’s dry conditions bring them in for water. Using ant sprays just outside a house can keep them from crossing your threshold, but spraying a larger area can send them fleeing inside. Indoors, household spray cleaner is a less toxic treatment and just as effective for infestations as ant spray. Baits, however, are considered the best hope to keep them from coming back.
Caulking or applying petroleum jelly on their entry points is also suggested. Ant experts have their own nonpoisonous tricks to keep Argentines outdoors.
John Kabashima puts sugar water reservoirs at the edges of his property “so they don’t bother me, only my neighbors.” In the spring, Argentines go for protein, such as that found in pet foods, and later in the year they’re drawn by sweets. For severe infestation he suggests the commercial spray and bait products Maxforce, which features a protein base with an active ingredient of hydramethylnon, or Terro, with deltamethrin.
Orange County Vector Control’s Mike Hearst keeps Argentines out of the house by what he calls “antscaping.” “Ants ranch aphids,” he says. “If I see aphids on a plant near the house I’ll swap it out for one that doesn’t attract aphids.”
Los Angeles County’s Richard Iizuka lives on the top floor of a four-story condominium complex in West Hollywood with Argentines comfortably ensconced in the pots on his deck. “As long as I keep them well watered I keep the ants outside. They come in for water or food. There’s plenty of food out there. If I water outside, they stay outside.”
Peter Nonacs, associate professor in UCLA’s department of ecology and evolutionary biology, considers Argentines “the perfect lab rat,” because of their ready availability and abundant supply. They’re never a problem at his house, though, because “we’re surrounded with cement.”
For more tips on conquering Argentine ants check out www.ipm.ucdavis.edu/TOOLS/ANTKEY/argman.html.
