[Pest Management] Fire Ants: Stinging the Food Industry

Fire ants sting. In 2003, USDA estimates put annual agriculture losses from this volatile insect at $750 million with $38 million in losses to livestock alone. In 2007, USDA estimated annual costs of nearly $6 billion for medical, agricultural and other control and damage expenses.

Impacting livestock and poultry operations, crops and plant electrical equipment, fire ants cause significant loss for the food industry. And their populations are continuing to spread.

Inadvertently introduced into the U.S. in the early 1900s, fire ants are currently well established across the southern states with expected north-ward movement in Oklahoma, Arkansas, Tennessee, up the Pacific coast and along the eastern seaboard into Maryland and possibly Delaware. Fire ants are a particular problem because work-ers are aggressive, have a potent sting, and have high reproductive potential.

The Problem. The ant is problem-atic in both urban and rural areas, for both homeowners and commercial establishments. Issues of particular concern to the food industry include:

• Poultry. According to James Parsons, extension area specialized poultry agent with North Carolina Cooperative Extension (NCCE), it is critical that fire ant populations be controlled around poultry houses because they can enter the structures as they forage for food, then establish mounds in houses, attack the chickens and forage on broken eggs. Their stings cause blemishes that can reduce the quality of poultry. In addition, poults will eat fire ants, which can result in the ant stinging the young fowl in the esophagus, preventing the poult from eating feed and causing reduced weight gain and increased feed conversion.
• Livestock. In cattle operations, fire ants can cause loss by foraging, infesting feed, impacting hay production, damaging electrical and other equipment, injuring or killing cattle, stinging workers and driving up medical costs for both workers and cattle.
• Agriculture. Fire ants will feed directly on some crops and on germin-ating seeds and seedlings of others. This can be a particular problem in the spring when the weather is dry. Fire ants also can cause loss where their tall mounds interfere with harvesting equipment, by chewing irrigation tubing during dry periods and by causing stand loss.
• Plant electrical equipment and utility housings. Fire ants frequently infest electrical equipment — chewing on insulation, causing short circuits, interfering with switching mechanisms and nesting in the met-al housings that surround electrical and utility equipment. In addition, they may carry soil into these units, which can cause corrosion, electrical short circuits and other mechanical problems.
• Worker safety. In all operations where fire ants exist, worker safety is of concern, as workers can be stung while fulfilling their day-to-day responsibilities. Though simply a nuisance for some people, others can be very allergic to the venom.

Control and Prevention.According to a Cooperative Extension System report, "No methods have been developed to successfully eradicate fire ants, but research may ultimately provide a method to eliminate this pest." Although complete elimination may not be possible, management and prevention techniques can help keep this pest under control.

Products. Drenches and baits are
noted by the NCCE as the most common methods for control of fire ants: 

• Drench insecticides may be purchased at most hardware and farm supply businesses, but it is advised that the local Extension Center be contacted for a list of approved products. Drenches work as a contact insecticide, so must trickle down through the mound and contact most of the ants, who will die in less than 24 hours. If the drench treatment does not kill all the ants in the treated mound, those who survive will construct a new mound 10 to 15 feet away. For this reason, the area should be checked several days after the initial application, and any new mounds treated.
• Baits also can be used to treat individual mounds. Baits are insecticides that have been mixed with ant attractants. Workers carry bait particles back to the mound and feed them to the queen. Although the insecticide kills the queen, workers may be active in the mound for several weeks before the colony disappears. Baits are fairly slow acting but are easier to apply than drenches and are best used when many mounds must be treated. 
• Baits also can be used in broadcast or banded applications. Broad-casting works well in areas of high infestation, but it is critical to follow label directions in determining where bait can be applied.

Organic options. Non-chemical meth-ods, such as cultural, physical, mechan-ical and biological control techniques should be the first options in organic operations, but when required, there are chemical products, such as plant-derived (botanical) insecticides, which are considered to be "of natural origin" or organic. (See the National Organic Program’s List of Allowed and Prohibited Substances at www.ams.usda.gov.)

Control methods for specific operations include:

Cattle. When dealing with fire ants in a cattle operation, the decision will need to be made as to where control is of most importance. In extensive operations, it can be extremely costly to treat all ant pop-ulations, so an assessment should be made to prioritize control areas. (An economic assessment sheet is available at www.extension.org. Search: "fire ant" cattle.)

Poultry. NCCE cites recent studies showing that banded applications work well around poultry houses, reducing the number of mounds in an infested area by approxi-mately 80 percent, and reducing the amount of bait that is required.

Electrical equipment. For safety reasons, only electricians or licensed pest control operators should treat electrical equipment. Specialized products and training are necessary to treat these sites safely and effectively. Once ants are eliminated, debris and soil should be removed from the equipment housings to reduce the possibility of short circuits. To prevent re-infestation, all sensitive electrical components should then be sealed, particularly those that are not insulated. A long-residual contact insecticide should also be applied around housings, avoiding the electrical circuitry or components, and a specifically labeled product applied to the housing itself or the mounting pad.If not employing an internal or contracted licensed professional, prod-uct options may be limited to those available at local retail stores. When using any pesticide, always follow label directions carefully and abide by all applicable federal, state and local regulations.

This article was compiled from Cooperative Extension System reports.