They cause damage to crops and property, and inflict painful stings on humans and animals. These ants infest millions of acres in 11 southern states. Eighteen counties along Tennessee's southern border are infested and the fire ants are expanding their range northward. The most common pathogen found in fire ants in South America is a microorganism discovered in Brazil in 1973. This same pathogen was found in fire ant colonies in Florida, Mississippi, and Texas in 1996, and has become the latest biological weapon for use against fire ants.
Workers transmit the pathogen to the queen through food exchange.
The disease slowly reduces her weight, and she lays fewer and fewer eggs, all infected with the pathogen. This further weakens the colony. Colony elimination has been shown to take from 9 to 18 months. However, in laboratory studies, ARS entomologists found that, after 3 months, infected colonies were already significantly smaller than healthy colonies. This microorganism does not harm plants, animals, or native ant species.