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Animal and Plant Health Inspection Service
U.S. Department of Agriculture
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Imported Fire Ants

Two species of Imported Fire Ants (IFA) were introduced into the United States from South America at the port of Mobile, Alabama. The black imported fire ant, Solenopsis richteri Forel, arrived around 1918 and the red imported fire ant, Solenopsis invicta Buren, in the late 1930's. Both species probably came to the port in soil used as ballast in cargo ships. Today, IFA infest more than 367,000,000 acres in Alabama, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, New Mexico, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia and Puerto Rico. IFA have an impact on agriculture and natural resources by damaging crops, agricultural equipment, and impacting wildlife. As an urban pest, IFA are a nuisance pest and can cause allergic reactions including rare instances of anaphylactic shock in humans.

APHIS works to prevent artificial (human assisted) spread of IFA by enforcing the Federal Quarantine (7 CFR 301.81) and works with State cooperators to regulate high risk commodities, such as nursery stock, hay and soil-moving equipment. Also, APHIS works with states, industry, and other Federal agencies to develop and evaluate the efficacy of regulatory treatments for high risk commodities, and revises regulations and procedures as necessary.

In an effort to manage IFA within the generally infested areas of the U.S, APHIS, along with cooperators in Agricultural Research Service, universities, and states, implement an Imported Fire Ant Phorid Fly (Pseudacteon spp.) rearing and release program. The first 2 species of this biocontrol agent, P. tricuspis and P. curvatus, were released from 2002-2009 and have become established in more than 65% of the IFA quarantined area. In 2010-2014 there were multiple releases of two additional species, P. obtusus and P. cultellatus, both of which have become established in limited areas. Phorid flies will not be a stand-alone biological control agent for IFA but will be an important tool in IFA management programs.

Pest Identification:


Quarantine Information

Program Support Documents

Other Resources


Herb Bolton
National Policy Manager
Telephone: 301-851-3594​

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