Management — Agricultural Control
Cattle Production Systems, Pastures and Rangeland
In a recent survey, ranchers said that fire ant problems are widespread and costly, but vary tremendously from ranch to ranch, even within the same locality. As a result, no one management plan can be used in all situations. Losses must be determined for each individual operation and treatment plans tailored to minimize those losses at an acceptable cost.
Ranchers can make two common mistakes when estimating fire ant losses and deciding on treatments. First, they may not include every loss caused by fire ants that takes money out of their pockets. Dead and injured calves and infested hay bales are obvious losses. However, a shorted-out air conditioner or the cost of treating mounds around the children's swing set also should be included, even though they are not directly related to the business part of the ranch. Survey results show, in fact, that electrical damage and pesticide expenditures are the two most common types of losses.
The second mistake involves treatment options. Fire ant "eradication" is not technically or economically feasible. Still, when many ranchers think of fire ant treatments they think of treating large expanses of land to try to kill all ants. At a minimum of about $15 per acre per year, treating large areas is not usually economical, although some methods can cut large-area treatment costs by up to half. What many ranchers fail to realize is that most fire ant problems occur on fairly small areas that can be treated rather easily and at a modest cost.
Worksheets 1 and 2 can help you categorize and tabulate losses. They come in two forms, Excel and Web formats. The Excel form can be downloaded and values entered into the correct columns and values will be calculated automatically. The web form can be printed out for those that do not have Excel. The first is for cattle production (Excel, Web), the second for hay production (Excel, Web). The eXtension fire ant website provides another assessment of fire ant cattle production costs. Once you have an accurate estimate of losses you can choose which treatment options are best for you.
Poultry Houses, Livestock Barns, and Feedlots
Imported fire ants on poultry farms can attack chickens and forage on broken eggs. Fire ant stings cause blemishes that can reduce the quality of poultry. Similar problems occur in animal feeding stations, barns and feedlots.
Field Crops and Commercial Vegetables
Red imported fire ants are considered beneficial insects in cotton and sugarcane production, and control is not recommended. However, fire ants can be detrimental to cotton and other crops when aphids are present. In cotton fields, fire ants are effective predators of boll weevils. Fire ants can be sampled using the beat bucket method, whereby the terminals of cotton plants are beaten into a plastic bucket to dislodge insects. In Louisiana sugarcane fields fire ants prey on sugarcane borers, Diatrea saccharalis (Fabricius). There, controlling fire ants increases the damage caused by the borers and the amount of pesticide that is needed. Fire ants may also prey on other pests such as corn earworm, armyworms and southwestern corn borer.
Fire ants occasionally feed on germinating seeds and seedlings of corn, sorghum, peanut, soybean, watermelon, cucumber, sunflower and other field or cover crops, particularly in the spring when the weather is dry. They sometimes cause stand loss. Okra growers are constantly battling fire ants because they are attracted to the oils in the plant. Where soybeans are planted flat rather than on raised beds or rows, tall fire ant mounds along the rows interfere with harvesting equipment. During dry periods, the fire ants sometimes chew irrigation tubing, as in vegetable crops.
Fire ants tending aphids
Fire ants feeding on corn
Fire ants feeding on sap
- Option 1:S-methoprene bait (Extinguish® ) is now registered for treating imported fire ants in cropland. Pyriproxyfen (Esteem) can be used by commercial growers in many tree fruits and nut orchards, as well as in certain vegetable and fruit crops. However, these baits are slow-acting and must be broadcast several months before maximum suppression is required. The most effective timing of application(s) and the economic benefits from control are still to be determined. Use where estimated losses exceed the cost of application, and monitor closely for secondary pest outbreaks in treated fields.
- Option 2:To prevent damage to corn and sorghum seedlings, treat the seed with a product registered for soil insect control, or band an insecticide such as Lorsban 15G (chlorpyrifos) over open furrows at planting where there is a history of stand loss. Gaucho® 480 Flowable (imidacloprid) and Cruser 5F (thiomethoxam) are registered as a seed treatment for sorghum and many other crops.
- Option 3:Few contact insecticides are registered specifically for fire ant control in watermelon, sunflower and other crops, although some products containing pyrethrins (Pyrenone Crop Spray and others) are generally labeled for ant control in these sites. Insecticides registered for other pests on these crops (and known to be toxic to fire ants) are occasionally used to temporarily suppress foraging ants when damage is observed and the crop is threatened.
Fruit & Nut Orchards, Vineyards & Blueberry Plantings
Although fire ants are mostly a nuisance to field workers in these crops, their overall economic and ecological impact is unknown. In pecan orchards, fire ants prey on pests such as pecan weevils and hickory shuckworms; however, they can encourage aphids by preying on their natural enemies. The ants' nest building aerates the soil of the orchard floor, which is beneficial, but they will feed on the meat of cracked pecans and can damage irrigation systems. Ant mounds may interfere with some types of harvesting operations. Chemical control is warranted only if the cost of control is less than the potential economic loss ants may cause. In pick-your-own operations, customer safety also should be considered.
- Option 1:S-methoprene bait (Extinguish®) is registered for use in cropland and abamectin (Clinch®) is registered for use in bearing citrus groves. Fenoxycarb (Award®) and pyriproxyfen (Distance®) are registered for use in young, nonbearing fruit and nut tree orchards. Pyriproxyfen (Esteem) can be used by commercial growers in many tree fruits and nut orchards, as well as in certain vegetable and fruit crops. Optimum timing of application(s) is yet to be determined. Where used, monitor closely for secondary pest outbreaks.
- Option 2:In pecan and citrus orchards, chlorpyrifos products (Lorsban® 4E and 15G) used to treat the orchard floor will temporarily suppress foraging ants. Spot applications around irrigation systems may help protect equipment from ant damage.
- Option 3:Few contact insecticide products are registered specifically for fire ant control in bearing peach orchards, vineyards and blueberry plantings, although some products containing pyrethrins (Pyrenone Crop Spray and others) are generally labeled for ant control in these sites. Turf areas around orchards, vineyards and blueberry plantings can be treated with registered products.
Nursery Crops & Sod Farms
See the Quarantine Section for information
Fish Farms & Production Aquaculture
Bodies of water such as rivers, streams, ponds, and lakes are highly attractive to fire ants. Fire ant mounds around ponds and on dams and levees of fish farms can be a nuisance and pose a threat to workers. When using insecticides in these areas, every effort must be made to avoid contaminating water sources. Fire ant baits contain very small amounts of active ingredients and can be applied on shorelines close to water, but not directly in the water. To minimize the risk of runoff, apply baits when ants are actively foraging so that ants collect the bait particles quickly. If individual mounds are treated, use products with lower toxicity to fish, such as acephate. Pyrethrins and rotenone products are highly toxic to fish and should not be used. Do not apply any form of insecticide if rain is likely to occur soon after treatment. Nonchemical mound treatments with steam or very hot water may be suitable for sensitive areas.
Fire ants can invade beehives and feed on developing bee larvae, occasionally destroying weak colonies. Fire ants can be useful to beekeepers. Waxmoth-infested boxes can be cleaned by placing the box on a fire ant mound. Once the moth larvae are consumed, the ants wil abandon the box and should leave the comb intact.
Hobbyist perceive little threat from fire ants in Tennessee; however, commercial beekeepers must abide by the USDA-APHIS-PPQ quaratine requirement to prevent moving fire ants with their bees. Imported fire ants can be moved to new, noninfested areas by hitchhiking on interstate commodities. For example, the current infestation in California's Central Valley was traced to shipments of beehives transported to almond groves.
To prevent such artificial movement, the U.S. Department of Agriculture (USDA) regulates the movement of articles that present a risk of spreading the imported fire ant to areas not currently infested. Regulated articles include soil, baled hay and baled straw stored in direct contact with the ground, plants and sod with roots and soil attached that are stored outdoors and are for sale, used soil-moving equipment, and any other article or means of conveyance determined to pose a risk. Beehives fall into the latter category.
To reduce the risk of moving fire ants with your bees, please refer to the publication from USDA, Beekeepers Don't Transport Imported Fire Ants.
Use chemicals with care because the bees will be affected by insecticides.
Suggestions for reducing fire ant activity in or near bee hives:
- Option 1: Treat areas around beehives using the two step method. Use products registered for the site in which hives are located. Conventional bait formations (e.g. those containing Hydramethylnon, fenoxycarb, pyriproxyfen or s-methoprene) are the safest to use near bee hives; dust formulations should be avoided.
- Option 2: Elevate the hive on a stand (blocks, bricks or other material)to limit the hive's contact with the ground. Moats or cans of nontoxic oil can be placed under the stand legs or Tanglefoot can be spread on the legs to impeed ant movement into the hive. Tanglefoot will lose its stickiness after awhile and will need to be reapplied. Oil level in the moats should be checked regularly too.
Wildlife Breeding Areas
Certain forms of wildlife are especially affected by ants during and soon after birth or hatching. The risk is greatest during warm months. Fawns are vulnerable because they are born in June and because they instinctively remain motionless in their hiding places. Quail and ground nesting waterfowl chicks are also attacked by fire ants. However, the effect of fire ants on wildlife populations over a large area has not been well documented. Fire ant control programs in wildlife areas are discouraged unless the benefits are clear and can be demonstrated. Many pesticides are toxic to wildlife (particularly to aquatic organisms) and may cause harm if not used properly.
- Option 1:Wildlife breeding areas are considered nonagricultural lands, and thus can be treated with products registered for this kind of site using the two step method.
- Option 2:Exotic game ranches and lands considered commercial agricultural areas can be treated in the same way as livestock grazing areas or pastures.
Maintaining Native Ant Populations
The states infested with imported fire ants have many native ant species, including other species of fire ants. Native ants often compete for resources with the red imported fire ant, attack mated fire ant queens trying to establish new colonies, and invade weakened fire ant colonies. Preserving and encouraging native ant species is considered the best defense against imported fire ants.