Keeping turf pristine and playable is no easy task, but it becomes much harder when ants decide to build their homes on greens and tee boxes. When ant mounds pop up, the negative impacts they can have on courses go far beyond a minor nuisance—to both superintendents and players alike.

Not only can ant mounds negatively affect the aesthetics and playability of courses, but they are impossible to predict; they just show up. In fact, a few years ago, one of our representatives in the Chicagoland area dealt with ant mounds on about 75% of his courses. Talk about a fast and widespread problem. We’re here to share the problems ant mounds can cause and explore effective solutions to eliminate them and control ant populations.

Problems Ant Mounds Cause

  • Turf damage from smothering. Since ant mounds deposit large amounts of sand and dirt on the turfgrass, sunlight and oxygen can’t reach it, smothering it.
  • An ununiform surface. Golfers are forced to putt around ant mounds on a playing surface that is not uniform, negatively affecting ball roll and detracting from what should be a fun experience.
  • Dull mower blades. Ant mounds are essentially sandy soil, and since course turf is cut so close, mower blades will become dull much faster than under normal conditions.

So how do you get rid of them? It’s important to note that using a rake or hose to destroy mounds will not stop the ants. That may curb them for the morning, but since ants build their colonies within just a few hours, they’ll be back by the afternoon. These quick methods—while seemingly good ideas—are like putting air in a punctured tire. In order to truly eliminate the problem once and for all, we need to understand both the biology and behavior of ants.

Multiple ant mounds can be seen emerging from turf.

Understanding Ant Species and Habits

The turfgrass ant (Lasius neoniger) is the most common ant to be seen on cool-season grasses in North America, however, they are nearly unheard of in the far western regions of the United States. Over 450 species of ants are present in North America, so figuring out what type you’re dealing with will determine the treatment method.

That’s why it’s important for superintendents to consult entomologists and/or pest control firms to figure out what the most common ants in their area are. What may be effective for one type of ant species may not necessarily be the best for another, as some products specify that they are ineffective on certain types of ants, like fire ants.

While ants, in general, can be present on courses all year, they do not emerge from hiding until the summer, which is when mounds will start popping up—but you’ll want to get out ahead of them in the spring.

Ant Conservation

Ants, while nuisances in some cases, can also be helpful. Ants act as natural aerators and consume other insects, so conservation efforts should be implemented where applicable. For example, treat greens, tee boxes, and a little bit off of the greens, but leave fairways and other areas that do not receive much (if any) foot traffic alone to preserve some colonies. In areas that are mowed but not playable, you can physically knock mounds down.

Preventative Measures

Before we dive into control and elimination, there are a couple best practices that can discourage ants from making your course their home.

  • Irrigate Properly. Water and moisture attract ants, and overwatering can create conditions favorable for ant infestations.
  • Aerate Regularly. Aeration promotes proper water and nutrient absorption by disturbing soil. It also creates a less-than-optimal environment for ants.

Control and Elimination Strategies

When ant mounds pop up, it’s time to take direct action with insecticidal treatments. There are plenty of insecticides for ants, all of which contain a neonicotinoid product and synthetic pyrethroid.

Neonicotinoids are insecticides that aim to kill certain types of insects and are water-soluble. Types of neonicotinoids include dinotefuran, imidacloprid, and clothianidin. Synthetic pyrethroids are another type of insecticide that is systemic and paralyzes the ant, providing quicker knockdown. Remember to choose a product that is approved for outdoor/course use and is designed to kill the specific ant species you are dealing with.

Systemics have to be watered in, and as the ants walk through it, it covers their bodies. Since ants do a lot of pruning—the act of cleaning themselves and each other—it spreads throughout the colony and eliminates it.

spraying pesticide with portable sprayer to eradicate garden wee
Portable sprayers are commonly used for insecticide applications.

Types of Ant Insecticides Plus Important Tips

Choosing the right insecticide is an important choice, so we’ve listed a few that are both popular and effective, along with some tips to make the most of whatever product you choose.

FMC’s Triple Crown T&O Insecticide contains dinotefuran and a synthetic pyrethroid, providing a fast-acting knockdown solution that stops ants in their tracks. While it can be applied throughout the growing season, the earlier it’s down, the better. To kill ants, apply 0.46 – 0.80 fluid ounces per thousand square feet.

  • Tip: Ants generally roam 20-30 feet away from the mound, so be sure to spray within a 20-30 foot radius of the mound, in addition to spraying the mound itself. Be sure to treat the entire radius, even if the mounds are on the edge of the green.

NuFarm’s Aloft contains clothianidin and can be utilized in either a single early treatment or applied as part of an ant control program from April through September. For best results, apply in the morning and then water at night for best results to allow the product to soak in. If watered immediately, the synthetic pyrethroid will be washed off, meaning the knockdown effect of the product will be stunted. If fire ants are an issue, Aloft is an EPA-approved fire ant control product. Apply 0.27 – 0.54 fluid ounces per thousand square feet. For best results, apply ten ounces per acre two weeks apart.

  • Tip: After mowing, leaving some clippings scattered can be beneficial. Why? Since the insecticide is still on the cut blades, ants could crawl over them and bring the systemic back to their colonies, including ones you may not know about yet.

BASF’s Alucion contains dinotefuran and alpha-cypermethrin, providing a powerful knock-down and repellent punch. Alucion is the only non-restricted use pyrethroid labeled for golf courses and is systemic. This single application product should be applied at a rate of 0.44 fluid ounces per thousand square feet.

  • Tip: Be sure to consult each product’s label and SDS before use.

What sets these products apart from others is that they provide more than just knockdown; products that use only a synthetic pyrethroid are unlikely to allow you to get control of the colony. Products that combine the power of neonicotinoids and synthetic pyrethroids are your best bet for eradicating colonies and ensuring a beautiful, uniform course environment.

When it comes to managing ants and other insects on your course, we have you covered. Whether you’re looking for information on our products or are looking for advice, your representative is here to help!