Biological control of fire ants: an update on new techniques.

OBJECTIVE To review the present understanding of biological control methods for imported fire ants (IFAs). DATA SOURCES We searched MEDLINE, Biological Abstracts, and the US Department of Agriculture Formis Ant Literature database. STUDY SELECTION All articles published in the last 10 years on biological control of fire ants were selected. RESULTS The decapitating flies Pseudacteon tricuspis, Pseudacteon curvatus, and Pseudacteon litoralis have been successfully released in the United States. The continued releases of multiple species of decapitating flies will expand the area of impact, applying greater pressure on IFA populations throughout the southern United States. The microsporidium Thelohania solenopsae causes the slow demise of a fire ant colony. The advantages of T. solenopsae as a biological control agent include debilitation of queens, specificity for IFAs, self-sustaining infections, and lower relative tolerance to chemical pesticides. Solenopsis daguerrei has also been shown to have detrimental effects on IFA colony growth, the number of sexual reproductives produced, and the number of host queens in multiple queen colonies; however, this parasite is difficult to rear in the laboratory and to introduce into IFA colonies. CONCLUSIONS It is unlikely that IFAs can be completely eradicated from the United States. However, technology using chemicals and/or natural control agents could eventually maintain populations at low levels if an integrated approach is used for control.