The invasive red imported fire ant, Solenopsis invicta Buren (hereafter, fire ants), is a significant threat to public health and a danger to livestock, pets and wildlife due to their venomous stings. The fire ant has invaded many countries and regions and has become a globally significant pest. The current major tool to manage fire ants are synthetic insecticides that are used largely as stomach poisons in bait products or contact insecticides in spray, broadcast, drench, and dust products for area and nest treatments. In addition to these insecticide products, repellants and fumigants can also be useful in some unique scenarios. The ever-increasing public concern about the potential adverse effects of synthetic insecticides on health and the environment has been a driving force for searching for safer alternatives to control fire ants. Tremendous effort has been made in developing biologically-based control for managing fire ants; however, natural products continue to be one of the most attractive sources of safe alternatives to synthetic insecticides. Here, we summarized the synthetic insecticides that are currently used in managing fire ants, available alternative products in the current market, and academic efforts in searching for fire ant natural toxins, repellants and fumigants.

The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), is a stinging, invasive ant from South America that has plagued the southern US since the 1930s. It is currently established in parts of California, including the Coachella Valley. We introduced and established the fire ant decapitating phorid flies, Pseudacteon curvatus Borgmeier and Pseudacteon obtusus Borgmeier (Diptera: Phoridae); Solenopsis invicta virus 3 (Picornavirales: Solinviviridae) (SINV-3); and the microsporidian fire ant pathogen Kneallhazia solenopsae Knell, Allan, & Hazard (Microsporida: Thelohaniidae) for the biological control of fire ants in this region of California. This is the first establishment of fire ant decapitating phorid flies in California. In addition, we demonstrated human-mediated establishment of SINV-3 and K. solenopsae in hot, dry, but irrigated, urban desert habitat.

Tawny crazy ants, Nylanderia fulva (Mayr) (Hymenoptera: Formicidae), are an invasive species found in states along the Gulf Coast of the USA. Their large populations are aggressive and can displace ant species already present in the area. Because tawny crazy ants are not territorial toward their own species within a locality, it was hypothesized that they may exhibit unicoloniality in their invasive range. To test this hypothesis, tawny crazy ants from separate locations in Florida were confined in small, enclosed arenas, and their interactions were observed and documented using a rating scale of aggression behaviors. Carbohydrate consumption also can affect aggression in ants, so starved and non-starved ants were tested separately. For non-starved ants, the level of aggression between worker ants increased if they were from different locations, but this interaction rarely escalated to fighting. When starved ants from different locations were given access to sucrose solution, the ants would exhibit trophallaxis rather than fighting over the food source. Queens from different colonies would quickly nest together. Thus, intraspecific aggression was not evident among tawny crazy ants collected from widely separated locations in Florida.

Nylanderia fulva (Mayr) is an invasive ant that is a serious pest in the southern United States. Pest control operators and homeowners are challenged to manage pest populations below acceptable thresholds. Contact and bait insecticides are key components of an Integrated Pest Management (IPM) strategy, however, little is known about their efficacy. In repellency and efficacy bioassays, N. fulva were not completely repelled by any insecticide tested, although fewer ants crossed a surface treated with Temprid^®. Few insecticides provided rapid control. Termidor^® and Temprid^® were the best performing with mean mortality of 100% in 13.4 and 19.0 days, respectively. In no-choice bait acceptance studies, it was shown that N. fulva generally had greater acceptance of carbohydrate-based ant baits (Advion^®, InTice^TM (gel), and InTice^TM (granular)). However, mortality was low for the InTice^TM baits in a 7-day bioassay. Maxforce^® Ant Killer Bait Gel and Advance^® 375A in the spring and Maxforce^® Complete in the summer and fall required the fewest days to reach 100% mortality. Bait active ingredients that resulted in the highest mortality were hydramethylnon and fipronil. These data on the efficacy of commercially available contact and bait insecticides provide valuable information to manage this invasive pest.