Daniel Gill, Merrill, Thomas A. | 5/26/2005 11:17:25 PM
By Dan Gill
LSU AgCenter Horticulturist
Fire ants inflict painful stings and create unsightly mounds in our landscapes, so most of us would be happier if there were no fire ants around. It’s interesting to note, however, that fire ants are excellent predators and help control such pests as fleas and ticks in lawns.
Although eradicating the fire ant in Louisiana is about as likely as doing away with the mosquito or the cockroach, with persistence and the correct application of insecticides, fire ants can be controlled. Just keep in mind there is no treatment that will eradicate fire ants from a yard permanently.
A variety of products and methods can be used to control fire ants effectively. The product chosen is primarily determined by the situation and the preferences of the individual doing the treatment.
When using a pesticide, always read the label carefully before you purchase it. Make sure you understand and are comfortable with how to use it and that it is appropriate for your situation.
Here are details on some of the various of options available for controlling fire ants:
Fire ant baits consist of an insecticide combined with a food material fire ants will consume. The bait is brought back to the colony and fed to other ants including the queen.
Baits may be applied to individual mounds or, better, broadcast over an entire yard. Even more effective than treating one yard, LSU AgCenter research shows that if neighbors get together and treat an entire neighborhood, the results are even better.
Use fresh bait, and apply it when the ground and grass are dry and no rain is expected for the next 24 hours. Apply baits when the worker ants are actively searching for food. There are a number of baits with a variety of active ingredients available.
Some products, such as those containing acephate, are applied as a dry dust. Ants walking through the treated soil get the dust on their bodies and transport the insecticide into the mound. Within a few days the entire colony should be killed. To use a dust, distribute the recommended amount evenly over the undisturbed mound.
Other insecticides used to control fire ants are mixed with water and then applied to the mound as a drench. These liquid mound drenches kill the ants underground but must be applied in sufficient volume to penetrate the entire nest. Generally, about 1 gallon of diluted mixture is poured gently over the top of each mound. These drenches usually eliminate mounds within a day.
Granular products offer another method of getting insecticide into fire ant mounds. To treat a single mound, measure the recommended amount and sprinkle it on top of and around the mound. Do not disturb the mound.
If the label specifies to water in the granules, use a watering can to gently pour 1-2 gallons of water over the treated mound to wash the granules into the soil. Unless the product completely penetrates the mound, ants will move to a different site through their underground foraging tunnels to avoid the insecticide.
A few active ingredients used in fire ant control products such as boric acid, pyrethrin, rotenone, citrus oil extract and diatomaceous earth are acceptable by organic gardeners.
Diatomaceous earth, a natural silica-based dust, will kill some ants, but it rarely eliminates ant colonies when used alone. Just be careful to avoid breathing in the dust-like particles.
Pouring 2-3 gallons of very hot (almost boiling) water into the hill will eliminate about 60 percent of the mounds treated, but this treatment must be done carefully – or the person doing the treatment could be burned. Very hot water also will kill any grass and plants it contacts, however, and surviving mounds will need to be treated again.
Some Things Don’t Work!
There also are some home remedies that simply don’t work well at all.
For example, spreading grits on a fire ant mound will only feed them or make them move. Placing orange or grapefruit peel on a fire ant mound will only make them move to another spot. Shoveling one mound on top of another in an attempt to force the ants to kill each other also is not effective.
Your parish’s LSU AgCenter Extension Office has an excellent free publication available called "Managing Imported Fire Ants in Urban Areas."
The publication, which also is available by visiting www.lsuagcenter.com, includes complete coverage of the problems fire ants cause and effective methods for how to control them. It also includes information on how to organize a community-wide fire ant suppression program. And there is a complete list of the types of fire ant insecticides, modes of action and formulations, with generic names of active ingredients and some examples of product names.
Get It Growing is a weekly feature on home lawn and garden topics prepared by experts in the LSU AgCenter. For more information on such topics, contact your parish LSU AgCenter Extension office or visit our Web site at www.lsuagcenter.com. A wide range of publications and a variety of other resources are available.