Karen Cambre, Sharpe, Kenneth W.
News article for April 16, 2018
Weather continues to be a big topic of conversation in agricultural circles, with copious amounts of rain in short periods of time and large temperature swings. I even saw a light frost on the ground in mid-April, go figure.
April 15 is a date that is easy to remember; however, not necessarily in a positive way. In terms of spring maintenance, I use that date to remind me to start fire ant control.
With oscillating temperatures, you want to make sure fire ants are active before beginning control methods. Ants are more active in warmer temperatures and slow down as we have passing cool fronts. Use the hot dog test method to determine ant activity. Put out a piece of hot dog on a skewer and lay it in the lawn grasses. Come back in 30 minutes and check. If it is covered in fire ants, then they are actively looking for food. If you do not have ants on the hot dog, you should wait for warmer weather.
A traditional control method is to apply insecticides to the nest. This method can have a relatively immediate impact; the problem is finding all of the nests. It is easy to see large mounds that tower above the grass. It is not so easy to see those flat mounds that are under the grass layer. If you just treat mounds, it is almost impossible to get a high percentage of control and then every time it rains, which is frequent, new queens split off old nests and start new mounds.
I like the method of using fire ant baits. This allows the worker fire ants to pick up baits as they are foraging for food and take baits back and share them with the whole colony. This eliminates the need for you to locate all of the ant nests. An added bonus to using baits is that your neighbors ants are feeding in your yard and you can help reduce their population also. While you might not feel that benevolent, the plus for you is fewer ants near your property lines to re-infest your lawn. If you could get neighbors on all four sides of you to control ants at the same time, you would get the greatest benefit because of the distance new ant populations would have to travel to get back to your property.
One consideration to using baits is that you typically need a few days of dry weather before applying baits, and you need about 48 hours of dry weather after applying baits to get the maximum benefit. Baits are usually corn grits that are impregnated with an insecticide or biological control compound. Ants pick up dry grits and take them back to the nest.
Another easy part of using baits is that you can apply baits in strips over the entire lawn. Ants will travel several hundred feet for food. Apply a bait strip every 25 feet or so using an inexpensive handheld broadcast spreader. Most of the products I use have a rate of 1.5 pounds per acre.
Insect growth regulators (IGR) offer an environmentally friendly control method. They control fire ants by interrupting their ability to reproduce. Worker ants are constantly dying off, and without the ability to replace workers, the ant colony will cannibalize itself and die off.
The IGR baits to consider are Extinguish, Award, Logic, Distance and Spectracide Fire Ant Bait. Extinguish is labeled to use around vegetable gardens and fruit trees.
To enhance the effectiveness of fire ant baits, you can treat individual mounds that you can see with an insecticide. I would wait 2 days after applying baits and then use Orthene 75S or Acephate 75S at the rate of 2 teaspoons per mound. You can also use Ortho Fire Ant Killer at 1 tablespoon per mound. These products come in small canisters that are easy to carry, and no water is necessary. Ants will work the soluble powder in as they come and go from the mound and if it rains, the product is will go directly into the nest.