Managing ants on putting greens

Dan Potter, Ph.D., is a professor of entomology at the University of Kentucky. He has conducted research on numerous turfgrass-damaging insects and beneficial insects. He can be reached at dapotter@uky.edu.

Q: Are ants on putting greens becoming more of a problem?

There seems to be an upsurge in ant problems on putting greens, which I attribute to the change in insecticides that are applied on and around greens today. Modern insecticides are more target specific than products such as chlordane and diazinon, which were used many years ago.

Those older insecticides not only controlled targeted pests such as cutworms, they also controlled ants and many types of beneficial insects. Neonicotinoids and Acelepyrn (chlorantraniliprole) have relatively little or no activity on ants.

Q: Before we talk about controlling ants on greens, is there anything positive about them?

Yes, ants are highly beneficial in a turfgrass ecosystem. They are aggressive predators of eggs of many insect species, including those that damage turfgrass. Only control ants where absolutely necessary. Let them work to suppress insect pests on the rest of the golf course.

Q: What is the basic life cycle of the turfgrass ant (Lasius neoniger) found on most greens?

New colonies originate when swarms of winged reproductive ants emerge from existing colonies and take to the air in late summer. After mating, the new queens shed their wings and burrow into the soil to establish a new colony.

Mated queens prefer areas in full sun that keep the colony warm. They start laying eggs in late winter. The colony grows rapidly in late spring and early summer as the ants enlarge their nest and foraging area and increasingly more workers are reared. The number of mounds varies from a few to dozens per colony and increases from early spring to mid-summer.

Production of males and new queens in late summer completes the cycle. Once a nest has been established, the resident queen may survive and lay eggs for several years.

Control ants the first time you see mounds on the green, usually in March and April in the Midwest. It is important to control ants when you first see the mounds before the population gets out of hand.

Q: Where are ants found on greens?

Our research and observations indicate mounds are found around the edge of the green, usually within six feet of the green perimeter. Mounds start at the edge of the green in the spring and move inward as the season progresses.

The mounds we see on greens are outposts and used for foraging for dead insects found on the perimeter of the green. Mowers do a great job of depositing dead insects along the perimeter of the green. The main nest is outside the collar in natural soil of the
surrounds.

Q: What strategies do you recommend to control ants on greens?

Control the mounds when you first see them. If you broadcast spray an insecticide, only treat the outer six feet of the green, the collar and a few feet into the surround. We have found spot treating only the mounds as they appear is an excellent way to control ants.

Pyrethroids (e.g., bifenthrin, lambda-cyhalothrin) and combination products that contain a pyrethroid work well to control ants, but be aware the control is only effective for about four weeks. Pyrethroids only knock back the worker ants. It is difficult to control the queen, so over time the colony recovers and the mounds return. Spot-treating with Advion Fire Ant Bait or Maxforce Fine Granule Insect Bait also can be effective.

I am not aware of any cultural practices that control ants on greens.

Q: Anything else to add?

I am a huge fan of ants. Do not eliminate them. Control them where necessary. They are the primary biocontrol agent for grubs. Ants are our friends.