Fire ant

Fire ants are stinging ants of the genus Solenopsis, of which there are 266 species. They include Solenopsis invicta, commonly known as Red imported fire ant (RIFA).

Each colony produces large mounds in open areas, and feeds on young plants and seeds. Solenopsis often attacks young animals and can kill them. For humans it has a painful sting – hence the name fire ant – and the aftereffects of the sting are deadly to some individuals. The worker ants are blackish to reddish and vary from 3-6 mm in length. Solenopsis has a very distinctive two-segment antennal club. This is most visible in the front view of the female reproductive ant.

Solenopsis invicta, or Red imported fire ant, was accidentally introduced into the United States via Brazilian cargo entering the port of Mobile, Alabama in the 1930s. The ants have since spread from coastal areas of Alabama and now infest large parts of the U.S. South, creating a nuisance to farmers and homeowners alike from central Texas to Maryland. Since 2001, anthills have been found in Australia, Taiwan, and China.


Some species of Solenopsis include:

  • Solenopsis xyloni ““ southern fire ant
  • Solenopsis richteri ““ black imported fire ant
  • Solenopsis molesta ““ thief ant
  • Solenopsis invicta ““ red imported fire ant
  • Solenopsis iritatia ““ Floridan Fire Ant, or Red Imported Flordian Fire Ant

Also notable is the only British representative of the genus, Solenopsis fugax. Horace Donisthorpe found a large colony of these ants at Sandown.

Organic fire ant control methods

To kill fire ants without resorting to costly and poisonous chemicals, simply melt 1/2 bar of lye soap in 5 gallons of water. Pour in a circle around the mound to prevent ants from escaping, then stir them up and drench thoroughly. This will kill the ants instantly without polluting your lawn or garden, and is totally safe for vegetable gardens and pets.

Ants often build nests in potted plants and nursery containers. Diatomaceous earth, dusted on your skin and clothing, will repel the ants and prevent their stings. This does not kill them and becomes ineffective when wet, but it can make agriculture and greenhouse work much safer and more pleasant, without harming the environment or exposing workers to toxins.