Mississippi areawide fire ant suppression program: unique aspects of working with black and hybrid imported fire ants

Chemical and biological controls for imported fire ants (Solenopsis invicta Buren, the red imported fire ant, S. richteri Forel, the black imported fire ant, and their hybrid) are being investigated and demonstrated in a multistate, multiagency Areawide Management Program. The Mississippi component of the program offers the unique opportunity to implement the latest control technologies against monogyne (single queen) black and hybrid imported fire ant colonies because sites in the other participating states (Florida, South Carolina, Texas, and Oklahoma) are dominated by polygyne (multiple queen) red imported fire ant colonies. Several observed and potential differences were examined between populations of black/hybrid fire ants and populations of red imported fire ants. Lower nest density of monogyne black and hybrid fire ant populations (range 19–52% of mean nest density at other sites) required modification of sampling protocols. Pseudacteon curvatus Borgmeier (Diptera: Phoridae), a phorid fly collected from Las Flores, Argentina, where S. richteri is present, was established at the Mississippi sites because it preferentially attacks black and hybrid imported fire ants; at the other sites, P. tricuspis, a phorid that parasitizes red imported fire ants, has been released. Other potential differences in management of black, hybrid, and red imported fire ants are discussed.