Fire alarm

Red imported fire ants have become an increasingly bothersome hazard to both golfers and golf courses, if only because they have now completed their East-West journey from sea to shining sea with their arrival in the Palm Springs golfing mecca of the Coachella Valley in California. Of necessity, golf course superintendents throughout the southern half of the United States have learned techniques for controlling the ant populations at some expense, but eradication of the aggressive pests once they are established remains problematic.

Although somewhat dated, a 1998 study by a trio of researchers at Texas A&M’s Department of Agricultural Economics determined that Texas golf courses in the cities of Austin, Dallas, Fort Worth, Houston and San Antonio alone spent an estimated $30 million on fire ant control and damages that year. Another researcher from the Texas Agricultural Extension Service named the red imported fire ant “the single most prolific pest in turfgrass.” While that label may be a bit of an exaggeration, given that the northern half of the U.S. is essentially immune to the cold weather-hating ants, southern superintendents who have to add another line item to over-stretched course maintenance budgets to protect their customers, their maintenance workers and equipment, course wildlife and even the electrical components of irrigation controllers, generators and other power sources might agree.

Visible evidence that red imported fire ants have taken up residence at a golf course varies by geography. Typically, from Florida and throughout the southeast to Texas, the ants will create relatively tall mounds of dirt that they’ve removed from underground nesting areas for the queen and younger ants. In the California desert areas, however, where the water table is significantly lower than in the southeast, particularly in recent years, the ants generally only create small piles of dirt above ground, according to Bobbye Dieckmann, field supervisor for the Coachella Valley Mosquito & Vector Control District. As in other parts of the country, those tend to be concentrated in golf course areas where there is less maintenance and mower traffic, in roughs or up against bunkers or near trees or other recently sodded areas.

The number and proximity of mounds to one another also varies by geography, says Dr. Paul Nester of the Texas A&M AgriLife Extension, who along with his predecessor Dr. Bart Drees has done a considerable amount of research on fire ants.

“In the southeast, they tend to be single queen mounds, while Texas mostly has multi-queen mounds,” Nester says. Because the fire ants can be extremely territorial when there is only one queen in the mound, single-queen mounds are farther apart, while mounds hosting multiple queens are less concerned by the presence of other ant colonies, so those mounds are frequently closer together, according to Nester.
 

Treatment strategies

Most experts recommend a combination of treatment protocols for effective fire ant control. For turfgrass areas with widespread fire ant populations, the first step should be a broadcast application of an insect bait fatal to ants when it is ingested. The forager ants who are constantly on the lookout for food and moisture to bring back to the queen and the colony will locate the bait and take it deep into the ant burrow where, if the queen consumes it, the colony will eventually die out. Bait products can include frequently used baits such as Advion, Extinguish or Extinguish Plus, Probait, Amdro, Ascend, Award and others, and should be applied either annually or semi-annually, depending upon the geographic region and the extent of infestation. The recommended density of application is between 1 and 1∂ pounds of bait per acre. Since most of the baits are water soluble, it is necessary to apply the baits in the affected areas between watering periods.

For problem, heavily populated mounds on the surface, a variety of either chemical or bait-formulated insecticides can be applied directly to the mounds. Chemicals can be either instant acting or slower acting but longer lasting, depending upon a superintendent’s preference, needs and budget. Some of the slower acting but longer lasting products can be found in granules like Bayer TopChoice or Taurus G insect granules. The problem with those types of treatments is that while they will kill the older foraging ants on or just beneath the surface, the poison will not reach the queen or the rest of the colony buried deep within the mound.

“We tell superintendents to develop a plan for treatment based on their situation, rather than just reacting to a problem infestation,” Nester says. “I hate it when maintenance workers just drive around with a jug (of insecticide) and hit the various mounds. They kill some, but the rest of the ants just move somewhere else close by.”

One reason for the significant spread of the ants since their arrival from South America in the 1930s is that the ants actually mate with the queen in the air, and new colonies form wherever the queen lands, enters the burrow that her attendants build for her, and begins laying thousands of eggs. Dieckmann says that studies in the Coachella Valley area have shown that queens on mating flights can fly 12 miles or even more in a single flight, depending upon the wind. The ants have been reported as far north as Kentucky and the Tidewater area of Virginia, but are not likely to go much farther north because of their aversion to extreme cold. Ironically, although neighboring Texas and California have the ants, USGA agronomist Brian Whitlark says that to his knowledge, the ants have not become a problem for Arizona golf courses, jokingly adding “maybe that’s because of our tough immigration policies in Arizona.” Actually, says Kai Umeda of the Arizona Extension Office, it’s more likely due to the state’s stringent agricultural quarantine programs that closely monitor incoming nursery and turf stock and quickly eliminate any fire ants detected.
 

Low- and high-tech solutions

Anyone who has ever inadvertently disturbed a red imported fire ant mound and failed to notice it is well aware of the painful consequences of trashing the ants’ happy home. Fire ants will respond immediately, can both bite and sting simultaneously when they latch on, and neither event is fun. Some people, in fact, are allergic to the ant venom, and can go into anaphylactic shock or even die. Bill Davidson, superintendent at the Country Club of Naples in Florida, says that one of the club’s pros didn’t know he was allergic to the bites, and had to be hospitalized after an attack.

There are numerous specifically designed products for treatment and control of fire ants, but some effective tricks of the trade are definitely low-tech. For instance, one way of determining the presence and density of a fire ant population in the area is simply to leave a common hot dog in the vicinity where you suspect an infestation and check it the next day for the number and species of ants it’s attracted. (To my knowledge, there have been no studies to date on whether the ants prefer all-beef, pork, skinless or even kosher hot dogs, so probably whatever the snack bar is serving will work fine.)

In addition to damage caused to mower blades and other maintenance equipment by the ant mounds, the red imported fire ants — and some other ant species as well — are attracted to the heat and electricity generated by various types of golf course maintenance equipment such as irrigation controllers, generators and other electrical equipment. The ants often nest in the machinery or cable housing, and even chew on the electrical wiring, which causes problems in two ways: the ants can short out circuitry either by piling damp dirt for nesting on it or by clogging the circuitry with their corpses after being electrocuted — kind of a good news, bad news result.

“The boards in those irrigation boxes are expensive, and we’ve had a few fry out fuses due to the ants,” the Country Club of Naples’ Davidson says. He has a simple deterrent to the power-crazy ants, however. “We’ll put mothballs in a cup in our irrigation boxes,” he says. “Urinal cakes work too. They fumigate the boxes and the ants, like other insects, can’t hold their breath, and they hate the smell, so they won’t stay in there.”

While the mothballs and urinal cakes don’t dent the maintenance budget much, the bait, insecticides and labor to keep the fire ants under control account for a $2,500 annual line item in his budget, Davidson says.

There are also more sophisticated deterrents to fire ants nesting in on-course equipment. The afore-mentioned Texas AgriLife Extension Service’s extensive library of fire ant research includes an article dedicated to the “Evaluation of ARINIX Permethrin Impregnated Nylon Plastic Strips in Preventing Fire Ant Invasion in RainBird Par + ES Irrigation Boxes at Bear Creek Golf World, Houston, Texas.” So, nylon plastic strips or mothballs, take your pick.

Research is also ongoing into ways to enlist Mother Nature’s help in controlling and eradicating fire ant colonies. Scientists are looking into the introduction of phorid flies, otherwise known as humpback flies, into the Oklahoma and Texas areas in particular. Phorid flies are natural enemies of the red imported fire ant, and wreak havoc on them in gruesome but effective ways. The female phorid flies pounce on the ants and lay their eggs in the ants’ abdomens. As the fly larvae hatch and grow, they essentially eat their way through the ants until they actually separate the ants’ heads from their bodies, finally killing them. At that point, other phorid flies lay their eggs in the ants’ detached heads, starting the cycle all over. Eventually enough ants are killed to essentially eradicate the colony. As Nester noted, with some scientific gallows humor, those infected ants are known as “zombie ants” since they are essentially the walking dead once the fly larvae hatch. Nester says, however, that the strategy has not been perfected thus far, due to the fact that there are multiple species of phorid flies, and they too are territorial and do not co-exist well with other phorid fly species.

Dieckmann also noted that a biological control technique is currently under study. A virus known as the SinV3 virus could conceivably be introduced into the fire ant colonies which would render the ants incapable of reproducing or eating.

In the meantime, however, the scientific consensus is that golf course superintendents are best advised to combine prevention and cure techniques to control their fire ant populations, using the combination of fatal bait to eliminate the queens and other worker ants deep in their mounds, while spot-treating particularly troublesome mounds and foraging ant populations with contact insecticides. As for golfers, they are advised to heed any local rules allowing them to take relief from any lies in the vicinity of fire ant mounds, and if there is no such rule at their course, just take an unplayable. They’ll be glad they did.