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United States Department of Agriculture

Agricultural Research Service

Title: Monitoring and Management of Red Imported Fire Ants in a Tropical Fish Farm

Authors
item OI, DAVID
item Watson, Craig - UNIVERSITY OF FLORIDA
item Williams, David

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 4, 2004
Publication Date: December 15, 2004
Citation: Oi, D.H., Watson, C.A., Williams, D.F. 2004. Monitoring and Management of Red Imported Fire Ants in a Tropical Fish Farm. Florida Entomologist. 87(4): 522-527.

Interpretive Summary: Tropical fish farms provide a prime habitat for the red imported fire ant, Solenopsis invicta, which is an invasive, stinging ant that has spread throughout the southern United States. It can be a serious health hazard to hypersensitive individuals, and the presence of large populations can interfere with operational activities. Fish farmers typically work barefoot along the pond banks and because the banks provide an ideal habitat for fire ant colonies, the probability of being stung is very high. Fire ants are not controlled because of the fear of detrimentally impacting fish being raised in ponds with insecticides. Scientists in the Imported Fire Ant and Household Insects Unit of the ARS Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, Florida were contacted by the University of Florida Tropical Aquaculture Laboratory to develop a program for controlling imported fire ants in tropical fish farms. Baited stations in combination with maps generated by geographical information system software were used to estimate locations of fire ant nests in an attempt to monitor fire ant populations. The most useful maps could be generated when fire ant populations were high, and a single fire ant was the threshold used to denote a positive bait station. The most efficient method of controlling fire ants is the application of ant bait. Areas around fish ponds were treated with a fire ant bait that contained the insect growth regulator methoprene. This bait was selected because of its low toxicity to fish and that methoprene formulations are used for mosquito control in aquatic ecosystems. Fire ant nest densities declined 57% within 4 months. In contrast, nest densities increased 86% in untreated areas. Fire ant populations declined an average of 68% and increased 110% during the summer for treated and untreated areas, respectively. Employees at the facility also perceived a substantial reduction in the number of fire ants in treated areas Fire ant nest densities and populations began to increase by December. No fish mortalities related to the ant baiting were observed during the study.

Technical Abstract: Tropical fish farms provide a prime habitat for the red imported fire ant, Solenopsis invicta Buren, which is an invasive, stinging ant that has spread throughout the southern United States. Stings can be a serious health hazard to hypersensitive individuals, and the presence of large populations can interfere with operational activities. The most efficient method of controlling fire ants is the application of ant bait. However, most fish farmers are reluctant to use baits or other chemical methods of control because of the unknown risk to fish. Baited stations in combination with maps generated by geographical information system software were used to estimate locations of fire ant nests. Maps of estimated fire ant locations encompassed from 9 to 73% of actual fire ant nests surveyed when there was a minimum of a single fire ant within a station. Low percentages of overlap between mapped areas and fire nests were associated with low nest densities and when higher ant count thresholds were used to indicate positive stations. Ant bait containing the insect growth regulator methoprene was broadcast between ponds, with some unavoidable bait entry into ponds. Fire ant nest densities declined 57% within 4 months. In contrast, nest densities increased 86% in untreated areas. During the summer, fire ant populations declined an average of 68% and increased 110% for treated and untreated areas, respectively. Fire ant nest densities and populations began to increase by December in both treated and untreated areas. No obvious fish mortality related to the ant baiting was noted during the study.

Last Modified: 9/10/2014
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