Integrated Pest Management: Fire Ants

The following information on fire ants is compiled from the NPS IPM Manual, university publications, pesticide labels, and Internet resources. Use it as a source of basic information to implement your IPM program for fire ant management. Formulate your pest management plan or activity within the framework of the management zones where it will be implemented and give full consideration to threatened and endangered species, natural and cultural resources, human health and safety, and legal responsibilities. Fire ants are aggressive and swarm over anyone and anything when their nests or mounds are disturbed. Stepping on a mound is almost unavoidable when walking in heavily infested areas. Many mounds are not easily seen and have lateral tunnels extending several feet away from the mound just beneath the soil surface. Ants defend these tunnels as part of their mound. A person who stands on a mound or one of its tunnels, or who leans against a fence post included in the defended area, can be attacked. Typically, the ants can be swarming on a person for 10 or more seconds before they grab the skin with their mandibles and inject their stingers. In infested areas, fire ant stings occur more frequently than bee, wasp, hornet, and yellow jacket stings. Although a single fire ant sting hurts less than a bee or wasp sting, the effect of multiple stings is impressive. Some people experience a generalized allergic reaction to a fire ant sting and each sting usually results in the formation of a pustule within 6 to 24 hours. The majority of stings are uncomplicated, but secondary infections may occur if the pustule is broken, and scars may last for several months. However, if a sting leads to hives, chest pains, nausea, severe sweating, loss of breath, serious swelling or slurred speech, the person should receive emergency care immediately. Persons hypersensitive to fire ant venom face a life-threatening situation. Individuals who are allergic to fire ant toxins may require desensitization therapy. Fire ants typically are ground nesting but will nest in boat hulls, wall voids, around plumbing, and under carpeting in structures. Mounds are often built adjacent to walls, tombstones, curbs, boulders, or slabs that hold and radiate warmth. They have also been found in outdoor electrical equipment, switch boxes, telephone booths, and light poles, apparently attracted to the electrical fields. Other infested sites include household electric meters, traffic signal control boxes, and even airport runway lights. Playgrounds, parks, and picnic areas in fire ant-infested areas go unused and it can be difficult to put up or take down a tent at an infested campsite without being stung.