Q: There are ants nesting in one of my garden beds. I searched them online and I think they are field ants. Will they damage the plants? The nest is right next to some tomatoes. Is it safe to use ant-killer in an orchard?
A: I asked the University of Minnesota Extension entomologist, Jeffrey Hahn, about ants in the garden. He says that ants are not likely to damage their plants, although they may disturb some roots with their tunnel. Usually, he says, owners can leave nests of field ants. They are beneficial insects that take advantage of some of the pests that eat the plants in your garden.
The other good news is that field ants will not enter your home and infest your kitchen.
But then there is the bad news.
Ants bite, so it can be difficult to avoid a nest that is close to tomatoes. Field ant nests can persist for years. And if you decide that you want to kill them, it can be difficult to do so.
There are some inaccurate tips here and there on the Internet on how to kill an anthill. It will not work to pour water on it, even if the water is boiling. It is dangerous and dangerous for the environment to pour gasoline into an anthill, and it will not work. Borax will not work. Herbal remedies such as mint, cinnamon and clove will not work.
The only way to permanently eliminate a nest of field ants is to kill the queen, and that can be difficult to do, since it could be 2 or 3 feet underground. Wisconsin Extension recommends making a hole with a rod or plug, and then pouring insecticide into the channel you created.
If you decide to follow that route, you should carefully choose an insecticide that is labeled for use near groceries, since its ants decided to nest next to their tomatoes.
Here you will find more information on the control of indoor and outdoor ants: https://extension.umn.edu/insects-infest-homes/ants#controlling-ants-outdoors-41811.
Written by U of M Extension Master Gardeners in St. Louis County. Send your questions to [email protected]