County Extension Agent

Although you may not have seen many signs of fire ants during the past few months, that does not necessarily mean they are not still around your landscape. During times of drought and extreme temperatures, fire ants just dig deeper down in the soil where conditions are more favorable to their survival. The deeper they go, the more likely there is some moisture and certainly the soil temperature is more moderate.

However, expect fire ant mounds to re-develop once temperatures start to cool and rain begins to fall. That’s why this is a great time to treat for fire ants.

To help control the proliferation of fire ants, Texas AgriLife Extension Service is spreading the word that the second week in September is Fire Ant Awareness Week. This is a great time to spread the word about fire ant management due to the fact that the fall is generally the best time of year to treat for fire ants.

First, the conditions are more favorable to perform outdoor activities. Second, fire ant baits are great tools to manage fire ants, but they are often slow acting, thus treating in the fall, provides time for the baits to eliminate the colony prior to the spring, which will hopefully leave your landscape free of fire ants for the spring.

Finally, the ants will be stocking up on food for the winter and will be more likely to pick up the bait which they consider a food source and carry back into the mound. Wait to treat when high temperatures are higher than the upper 80s to low 90s and low temperatures are above in the 60s or higher. This is when the ants will be the most active.

If you have a yard full of recently rebuilt fire ant mounds, then you may want to consider taking management actions now which could lead to fewer ants for the upcoming spring. Currently, the Two-Step Method for controlling imported fire ants is the most effective strategy available.

The first step, which is most important, is to thinly broadcast a fire ant bait product over the entire yard using a small, hand held spreader. Fire ants take up the insecticide-treated bait thinking it is food and carry it into the mounds. Once the bait is inside the mound, the slow acting product or growth regulator is spread from ant to ant and eventually to the queen. Baits are slow acting and can take 2 to 12 weeks to achieve maximum effectiveness. With the baits, the use rate generally ranges from one to one and one half ponds of product per acre of surface area. That equates to about 1/4 to1/3 pounds of product per average yard size. After reading the label you will see that for most fire ant baits, the active ingredient contained in the bait makes up less than 1 percent of the product. This means that over 99 percent of the product is inert product, generally ground up corn cob grit, the carrier where the active ingredient is contained and soybean oil which attracts the ants to the bait. These baits sometimes take a while to actually reduce the ant populations, but they will be effective for a much greater length of time and the results may lead to very low levels of fire ants the following spring.

To see if fire ants are actively foraging, place a small amount of bait or food, such as a hot dog or potato chips, by the mound. If ants cover the bait within ten minutes they are actively foraging. Also, only fresh bait products should be used. Fire ants will not pick up the bait if it smells rancid.

The second step is to treat individual mounds with a fast acting pesticide. There are many organic and traditional pesticides which are low in toxicity, such as pyrethrins, permethrins, acephate and other products. Individual mound treatment products can either be granular, liquid, or dust formulation. This step is ideally done three to five days after the bait product is spread because it exposes the mounds to both types of treatment.

It is important to note that the second step needs to be performed after the first step. The first step is intended to use the worker ants as the means of getting the slow acting material down to the queen ant. Once you eliminate the queen, then the colony will die out. The second step is intended to kill off much of the worker ants that cause problems to people, animals, and equipment, but after they have spread the slow acting bait through the mound.

Longer term control can be achieved when neighbors treat at the same time. Baits need to be fresh in order for ants to be attracted to them. Baits need to be applied when ants are actively foraging. Therefore, sprinkle a few granules near ants on a warm day. If the bait is detected within ten minutes, then it would be a good time to apply the bait.

Residents need to be flexible when choosing a date to treat because the product should not be applied when rain is forecast in the next 48 hours. Also, to extend the length of control, coordinate the application with neighbors. Imported fire ants travel from yard to yard, easily dispersing due to periodic mating flights. Also, colony movement readily occurs at this time. By eliminating fire ants in a larger area, it will provide a greater amount of time before a new queen will find her way into your yard and begin a new colony.

Some of the organic baits on the market are listed by the Organic Materials Review Institute are Safer Brand Fire Ant Bait and Green Light Fire Ant Control with Conserve. These products contain active ingredient Spinosad.

Spinosad is a product formed from a common bacteria found in nature. Once ingested by the fire ant, spinosad attacks the nervous system causing paralysis and death.

Some organic individual mound drenches that are listed by Organic Materials Review Institute are Safer Brand Fire Ant Mound Drench and Citrex Fire Ant Killer, both containing the active ingredient d-limonene.

D-limonene is an extract of orange oil released from crushed or grated lemon peels. When the citrus fruits are juiced the oil is pressed out of the rind. D-limonene is the oil left behind and collected. It destroys the wax coating of the insect’s respiratory system, thus when applied directly to the ant, it suffocates.

A relatively new active ingredient for fire ant management is fipronil. It can be found in the homeowner product Over N’ Out and in the Professional Product Chipo Top Choice. This is a contact granular insecticide that is broadcast across the entire landscape just like bait. The pros to using this product is that it is less sensitive to environmental conditions than the baits, which only work best when applied at a time when the ants are out actively searching for food. Because this is a contact product, the ants do not have to pick up the product and take it back to their mound, thus one can apply at any time of the year and still get excellent control of fire ants. In addition, control is expected to last a full 12 months. The major drawback to using this product is the price, it is several times more costly on a per area basis than standard broadcast baits referred to above.

To help in the effort to control fire ants and to see a listing of recommended products available to manage these pesky critters, the most widely requested Extension publication, The Texas Two Step Method: Do it yourself Fire Ant Control, has been updated. You can get an electronic copy of this publication by visiting the Somervell County AgriLife Extension Service home page at and clicking on the “Links” link, at the top menu bar, then “Extension Publication link”, then “Texas AgriLife Extension Bookstore”.