Insects & Other Pests ›
From an agricultural perspective, red imported fire ants are nuisances primarily because they annoy field workers and because their mounds may damage harvesting equipment. Livestock injury and crop damage are usually minor. Fire ants have a much greater impact on the orna-mental plant, sod, and landscaping industries because of problems associated with shipping infested plant material into uninfested areas of the country. Mounds discovered in previously uninfested areas of North Carolina are frequently traced to landscaping performed at commercial and residential developments. For the general public, two aspects of red imported fire ant infestations are particularly annoying: the unsightly mounds formed in lawns and yards and the painful stings received when mounds are disturbed.
Hot water (i.e., 90° F) and mechanical disruption have been used in many instances. Results of some preliminary evaluations at Texas A&M University have shown that these treatments will kill large numbers of ants; however, satellite mounds formed by surviving ants subsequently appear. Thus, these methods can have a useful, but temporary impact on fire ant colonies in areas situations where pesticides of any type are considered unacceptable. Other non-chemical mechanical devices that disrupt colonies do not have scientifically-based test data to support their effectiveness.
Research is underway to look at the use of biological control agents to control imported fire ants. These agents include parasitic flies and other ant species, as well as fungi and other microorganisms. These methods are not yet proven to be extremely effective by themselves but can help reduce fire ant populations as part of an IPM program. For more information about biological control of fire ants, visit the USDA-ARS website.
There are two basic approaches to chemical control of fire ants. An insecticide can be applied to individual mounds or it can be broadcast over a wide area infested with fire ant colonies. Individual mound treatments are usually more environmentally and ecologically acceptable because they use less insecticide and limit areas treated as compared to broadcast treatments, and they are likely to have less impact on non-target insects. Regardless of the method used, the objective is to kill not only the workers but also the queen, because she is the only ant in the colony that is capable of laying eggs. Always follow the label directions when applying any fire ant insecticide.