Summary of Losses from Insect Damage and Costs of Control in Georgia - 1997

VII. Fire Ants

B.L. Sparks, W. Hudson, J. Ruberson and K.G. Ross

Imported fire ants have been found in all 159 counties in Georgia as of 1997. Polygynous populations are present in eight Georgia counties; Barrow, Clarke, Clay, Early, Greene, Morgan, Oconee and Walton. Polygynous fire ant colonies reach higher densities than monogynous colonies and may be harder to control.

Imported fire ants are primarily a people pest. Fire ants interfere with hay harvesting and maintenance of pastures and recreational turf areas. They present the greatest problem around dwellings where direct contact with humans is most frequent. Concern arises from multiple stings often experienced by young children.

Fire ants act as both pests and beneficials in crop systems. In the role of pest, fire ants have a pronounced tendency to protect aphids from their predators, allowing aphid populations to explode unchecked. The costs incurred by this activity of ants are very difficult to quantify, but can probably be quite significant. In cotton, ant farming by fire ants actually appears to accelerate the destruction of aphid populations by a fungal pathogen. Such is not the case with other systems (e.g., cotton, soybeans, peanuts) where fire ants are aggressive predators, removing large numbers of pest caterpillars and other pests. They become particularly abundant in reduced tillage systems where their mounds do not suffer frequent disturbances, and can become key components of these systems. It is difficult to calculate the positive economic impact of fire ants in row crops, but if a single insecticide application is saved over 1 million acres because of ant predation on pests, the benefits accrued to growers would be somewhere between 6 and 10 million dollars. This may well be an underestimate of their full beneficial impact.

1. Average treatment costs per Georgia household for lawns and other surrounding areas was $20.90 (Diffie & Sheppard. 1991. In Imported Fire Ant Management: Results of applied Research/Result Demonstrations 1987-1990. The University of Georgia.) 2.7 million households in the infested area x 65% yards x $20.90 = $36,679,500 spent by homeowners for control.
2. Treatment costs for quarantine requirements in nursery and sod. Approximately $125 per acre are spent on 16,000 acres = $2,000,000.
3. Average medical costs related to fire ant stings were $4.95 per household according to Diffie & Sheppard (1991). Assuming 2.7 million households are in the infested area x $4.95 = $13,365,000.
4. Equipment damaged; mower, balers, etc., assume one incident for each 1,000 acres of infested crop or pasture land. Approximately 2.6 million acres divided by 1000 acres x $50 per incident = $130,000.