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Title: Area-wide Suppression of Fire Ants

Author
item Oi, David

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/22/2007
Publication Date: 11/14/2007
Citation: Oi, D.H. 2007. Area-wide Suppression of Fire Ants. Meeting Abstract.Proceedins of the Symposium on the Vision of Taiwan Plan Protection Development.1:41.

Interpretive Summary: Fire ants infest over 129.5 million ha in the United States. With their tremendous reproduction, mobility, and ability to occupy a wide range of habitats, fire ant eradication is at best very difficult. In the US, rapid and extensive spread of these stinging ants resulted in drastic attempts to eliminate or control the invasive pests including large-scale aerial applications of acutely toxic contact insecticides, and the applications of the less toxic mirex bait. Unfortunately, mirex accumulated in the environment and its use was banned. However, mirex bait has served as a model for the development of current fire ant baits which contain more environmentally compatible active ingredients including metabolic inhibitors (MI) and insect growth regulators (IGR). A blend of MI and IGR baits have been used in recent areawide suppression demonstration projects of the ARS Areawide Suppression of Fire Ants in Pastures project being coordinated by scientists at the USDA-ARS Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, Florida. One of the USDA-ARS scientists reviews the area wide project. Eradication of fire ants from the US is no longer pursued, but instead fire ant management practices are evolving to integrate both chemical and biological controls. The biological control agents include a fire ant pathogen, and tiny fire ant decapitating phorid flies from South America. These biocontrol agents have spread and are self-sustaining in the US. Perhaps the most compelling effect of biocontrol introductions is the potential delay in re-infestation in areas cleared of fire ants by insecticides. Development of treatment thresholds using food lures to assess fire ant populations may further facilitate the maintenance of acceptable levels of fire ant control and the continued presence of their biological control agents.

Technical Abstract: Fire ants, Solenopsis richteri and Solenopsis invicta, infest over 129.5 million ha in the USA. Fire ants, with their tremendous reproduction, mobility, and ability to occupy a wide range of habitats make their eradication very difficult. In the USA, rapid and extensive spread of these stinging ants resulted in drastic attempts to eliminate or control the invasive pests including large-scale aerial applications of the acutely toxic contact insecticide heptachlor, and the applications of the less toxic mirex formulated into a bait. Unfortunately, mirex accumulated in the environment and its use was banned. However, mirex bait has served as a model for the development of currently available fire ant baits which contain more environmentally compatible active ingredients including metabolic inhibitors (MI) and insect growth regulators (IGR). A blend of MI and IGR baits have been used in recent areawide suppression demonstration projects in the USA. Eradication of fire ants from the USA is no longer pursued, but instead long-term, areawide, fire ant management practices are evolving to integrate both chemical and biological controls. Two of the biological control agents are the fire ant pathogen Thelohania solenopsae and the fire ant decapitating phorid fly, Pseudacteon tricuspis. Introductions of T. solenopsae and P. tricuspis into red imported fire ant populations in the U.S. have spread and are self-sustaining. Perhaps the most compelling effect of the biocontrol introductions is the potential delay in re-infestation in areas cleared of fire ants by insecticides. Development of treatment thresholds using food lures to assess fire ant populations may further facilitate the maintenance of acceptable levels of fire ant control and the continued presence of fire ant biological control agents.