We have two large ant colonies (large black ants, not carpenter) in our lawn. The ground is soft where they are and I have tried pouring boiling water down the holes, using vinegar, etc but they keep coming back. What is the best way to permanently remove them? They pose walking hazards…
Ants are social insects that live in organized nests that contain many hundreds and sometimes thousands of ants. Ants can cause concern, however they are a nuisance rather than a destructive pest. They mainly feed on insects, including other ants. Usually, they do little damage to plants themselves, except by disturbing the soil around the plant roots and depositing it on the surface during their nest building activities. This can be a nuisance on lawns, as you are experiencing .
Unless nests are particularly troublesome, ants are best left alone. If a colony is destroyed it is likely that its place will taken by in-coming queen ants, which take over the territory and establish even more new nests.
Ants prefer dry, well-drained soil in an undisturbed, low traffic area. Your best defense is to keep your lawn healthy and stress free. Follow your lawn care schedule. Cut the grass the right height. Feed your lawn and water as necessary. If the lawn has an uneven surface due to years of ant activity, peel back the turf in the raised areas, remove excess soil and relay the turf. This is easier to do in the winter when ants are less active
The Ontario ministry of the Environment has approved the use of borax as well as diatomaceous earth, which is available at your local garden centre..Below is a link to a Gardening Guide on organic pest control : https://www.torontomastergardeners.ca/wp-content/uploads/2012/08/Organic-Pest-Control-Products.pdfor
Unless the infestation is particularly troublesome, the best remedy is to live with these beneficial insects. Most ants eat the larvae of lawn pests that they find among the roots of the grass.