Fire Ants

As noted in a previous post, Argentine ants are the most common  household pests in San Diego County. However, there are about 200 different ant species in California, including the southern fire ant (Solenopsis xyloni) and the red imported fire ant (Solenopsis invicta). A recent article in the Riverside Press-Enterprise discussed an infestation of fire ants in Rialto, where these pests have been devouring crops and threatening residents for the last 10 years. Fire ants came to the United States on cargo ships from South America in the 1930's. Today they are a problem that has cost millions in dollars per year, especially in Riverside and Orange counties. The battle against fire ants got tougher after funding for a statewide eradication program was cut in 2003. All of Orange County and parts of Riverside and Los Angeles counties are under a red ant quarantine, limiting the movement of plants and soil in those counties.

Fire ants vary in size, ranging from 1/16 to 1/4 of an inch long, and are yellow to dark red-brown. They have a stinger at the tip of the abdomen. Colonies range in size from 80,000 to 250,000 workers in a single-queen colony. Queens can produce approximately 1,500 eggs per day. They are called "Fire Ants" because of the fiery, painful sting they inflict. The venom on these tiny ants causes painful, itchy welts or blisters. For individuals who are allergic, the bites can be fatal.

Because their nests are so large, sometimes several treatments of insecticide are needed to reduce or eradicate the colony. Baits which contain an insect growth regulator (IGR) and/or a slow stomach poison can also be effective. Here in San Diego, we don't see many infestations of fire ants - but with populations growing nearby, we want to offer suggestions to homeowners that apply to control of all varieties of ants. Here are the basics:

1. Determine what the ants are attracted to and remove the source.

2. Vacuum trails, clean with soapy water or spray with window cleaner.

3. Locate entry points and fill with caulking or petroleum jelly.

4. Place ant bait stations or gel bait labeled for ant control near the entry points.

5. Continue to clean up trails, as baits require time to work.

6. If ant invasions continue, call your pest professional.