Knowledgebase

Destroy ant hills in lawn and kill Queen #825518

Asked April 13, 2023, 4:12 PM EDT

My name is Bill and I live in Oakland County. I am retired but do a little bit of lawn mowing and basic landscaping.

I have lawn customer who at the end of last year had more than 100 anthills in her 13,000 sq.ft. lawn, also in Oakland County. Perhaps more than 200 ant hills. Just ravaging her lawn.

I found out about Diatomaceous Earth Food Grade last year and planned on applying it to her lawn this year. I called the manufacturer and they told me the package would give me directions on how to mix the powder with water so I could make a slurry to apply to a large lawn.

But the Customer Service Rep reminded me about what has to be done to get rid of the ants permanently and that is kill the queen. And Diatomaceous Earth will not do that.

So she recommended I contact your dept. to get your advice on what product to use on all the ant hills, but also what “bait” to use to kill the Queen.

Also I need direction on when to apply the products. I am getting ready to spread Spring fertilizer on my customer’s lawn. Can I kill Queen Bees and get rid of all the ant hills while also fertilizing. Or should I fertilize first, then kill the Queen Ants and all the ants too.

Any advice will be welcomed. I need to see simple, step by step instructions on “what products “ to use and when and in what sequence. I want my customer to be satisfied with the results so I can get on with fertilization and growing new grass in various areas.

Looking forward to your advice. The sooner the better. I assume we are already into the season for killing ants and queens.

Thanks in advance for your help.

Bill VanHorn

4231 Crestdale Ave

West Bloomfield, Mi. 48323

Oakland County Michigan

Expert Response

All ants are fundamentally beneficial, especially in natural areas, but if you feel that they are in danger of causing significant damage, then you may choose to take measures to control them. The approach to management of ants in a residential lawn depends a lot on the type of ant and whether or not their presence can be tolerated. Most species of ants will not do significant damage to the turf. If the turf is well cared for in terms of nutrition and watering, the grass will grow to the point where you won't even know the ants are there within a few weeks. However, some species of ants in Michigan can bite and/or sting aggressively, or attack the grass itself, so you may choose to eradicate them from the lawn. For information about how to keep ants from becoming a problem and for how to protect pollinators while managing pests, visit our Gardening in Michigan page here: https://www.canr.msu.edu/home_gardening/tip_sheets/smart-lawns

Here are some options for getting rid of ant mounds in a yard:
The fastest approach would be to use an insecticide to kill the ant colony. You must use one that is labelled for use against ants in the yard (i.e. for outdoor use). Be sure to follow the label instructions very carefully. If you decide to go this route, I would recommend an insecticidal dust formulation, and sprinkling it on the entrance to the mound only. The ants will pick up the dust and carry it into the nest and kill other ants before they die. This dust will kill any insects it comes into contact with, so take care not to put it near flowers or anywhere that it might be picked up by bees or other pollinators. Also take care to keep children and pets away from the treated area. The insecticide label will contain detailed instructions regarding safety to humans and pets.
If the ants are entering the home, another option is to make a homemade ant bait. There is a recipe for a homemade bait in this MSU factsheet (https://pestid.msu.edu/insects-and-arthropods/pavement-ants/). The factsheet is for pavement ants, which may be a different species from the ant that you have in your lawn, but the bait may still work on your ants. If the ants don't seem attracted to the bait you may need to try a different bait (e.g. sugar or grease-based). Place the bait somewhere in the home where you see the ants and where it is not accessible to children, pets, or pollinators. The baits will take longer to kill the colony so be patient. It might seem like it is not working, but it may take 2 -3 weeks to kill the whole colony. This approach is not likely to work on carpenter ants. You will probably need to seek assistance from pest management professionals if you think you are dealing with carpenter ants. The website https://pestid.msu.edu/insects-and-arthropods/ has a great deal of information about most of the ants that are a problem for homeowners in Michigan.


An Ask Extension Expert Replied April 14, 2023, 1:40 PM EDT
I need a specific answer to my question about killing the Queen Ant.   The makers of Diatomaceous Earth Food Grade tell me their powdery product will kill the ants but to get rid of them permanently from a lawn that has 150-200 anthills, which is destroying my customer’s lawn.  I need to kill the Queen. And the makers of Diatomaceous Earth tell me the only way to kill the Queen is to bait the entrance in addition to using their powdery product.   Can you name a specific bait that the ants will take back to the Queen that will kill the queen.     The issue is that my customer’s lawn has not been properly cared for in the past and I need to rid the entire lawn of ants so a healthy lawn can be created.  



On Fri, Apr 14, 2023 at 1:40 PM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied April 14, 2023, 4:34 PM EDT
Active ingredients that will kill ants include boric acid, spinosad, and many pyrethroids (e.g. deltamethrin, lambda-cyhalothrin, gamma-cyhalothrin). It is not so much the active ingredient that matters as much as the formulation and the application method. Most of the products available to homeowners will be effective as long as the label includes the intended use and the user follows the directions. The trick to killing the queen is using a product that is slow-acting, so that the workers carry the toxin back into the nest. They will then feed it to their nest-mates and eventually the toxin will reach the queen.  
Without knowing what species of ant you are contending with, I can't tell you how many colonies you have. My guess, however, is that you have tens or hundreds of queens to kill to achieve your goal of eradication of ants from the yard. This means that you will probably need to use a powder formulation applied to each anthill, or a granular formulation that you would broadcast throughout the yard. Be sure to follow the label directions to ensure the product's effectiveness, the safety of you and your family, and in order to protect our wildlife. 
Pyrethroids are extremely toxic to bees and other beneficial insects. If you choose a product with a pyrethroid as an active ingredient, do not apply it to an area with blooming flowers, or where bees are nesting in the soil. This article from MSU Extension can help you tell bees from wasps that you might find nesting in the soil: https://www.canr.msu.edu/news/bee-wasp-or-hornet-nest-which-one-is-it
An Ask Extension Expert Replied April 17, 2023, 8:27 AM EDT

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