What can I do about fire ants in my horse paddocks? You have a few options, one easy, and one not so easy.
But first let’s cover the basics of how fire ants live and what they can do to horses. In the US, there are basically 4 types of fire ants, all stinging, all a potential danger. Most commonly, they reside in the south and south east. These stinging and biting ants live in huge mounds, deep into the ground. Larger mounds can be two to three feet wide at the top, with burrows going 18 inches or more into the ground. In any given pasture, you can typically find 40-300 mounds per acre.
Each mound has a complete colony of fire ants, and usually more than one queen. Each queen is capable of producing 1200 eggs per day. These guys are easily disturbed by movement, and swarm to attack the source of disruption. They are drawn to electricity and water, so activity is high around electrical sources and troughs, as well as after a rainstorm. They are omnivores, and eat plants and animals, including ticks.
The sting of a fire ant is itchy, painful, and unfortunately, long lasting. Horses are most susceptible to their sting when rolling or resting in the pasture. Often times, you will need to interfere and use a horse or sweat scraper to remove the ants from your horse. For the healthy adult horse, it’s likely that an encounter with fire ants will necessitate a call to the vet for anti-inflammatory medications, antihistamines and pain medications. Secondary complications can include laminitis, respiratory difficulties, and abortion in pregnant mares. Younger or older horses may require euthanasia. These little ants are not to be messed with - at all!!
So how do you deal?
In many fire ant heavy areas, there are specialists that can treat your pastures on a regular basis. You can opt to treat the pastures as well, using treatments found at your local garden supply. Fire ant poison comes in the form of bait, which is sprinkled around the perimeter of the mound. When the ants bring the bait into the nest, it is pulverized, eaten, and regurgitated by the worker ants and fed to the queen and young ants. Over a few weeks time, the queen(s) are unable to lay healthy eggs and the colony dies. When you are shopping for the appropriate bait, look for one that is specifically designed for pastures, as this will be safe for your horses. The chemicals hydramethylnon, pyriproxyfen, s-methoprene, and fenoxycarb are the common ingredients are proven to be effective.
If you have the red imported fire ants in your pastures, you can opt to purchase phorid flies and release them. They are natural enemies of red imported fire ants, and can be very effective at driving them away to find other places to nest.
Your other option is to try and cook them with boiling hot water. This is a time consuming task, and best done on a sunny day after a rain, when the ants are likely to be closer to the surface of their mound. Pour scalding hot water into the mound and cross your fingers. You may need to check the mounds later and poke with a stick to see if any ants come out, in which case boil and repeat. This method is questionable, as the queen lives deep into the earth and may not be reached. Get ready for many trips with your kettle!
What have you done in your area to help your horses have ant free pastures?