The approach to management of ants in the lawn depends a lot on the type of ant and whether or not you can tolerate their presence. Most 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 in to the point where you won't even know the ants are there. However, there are some species of ants in Michigan that can bite and/or sting aggressively. A few others attack the grass itself. Please keep in mind that all ants are fundamentally beneficial, especially in natural areas. If you feel that they are in danger of damaging your home or injuring your family, then you may choose to take measures to control them.

Here are some options for getting rid of ant mounds in your yard:

As I already mentioned, caring for the turf properly will allow it to fill in the patchy areas and grow more densely. The first step would be to get a soil test from the affected area in order to identify if there are any nutrient deficiencies that are preventing the turfghass from thriving. You can purchase a home soil test mailer from MSU Extension by visiting your local MSU Extension office or by visiting the MSU Extension bookstore at shop.msu.edu.

Another approach would be to use an insecticide to kill the ant colony. You would have to 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. The label will also contain instructions for keeping the product from entering groundwater and/or nearby waterways. Most of these products are highly toxic to aquatic life, including fish. You can read more about the risk that these product pose to the environment by visiting the National Pesticide Information Center website.