You can check for grubs by lifting a piece of turf. If the patch rolls up like a carpet, or the grass has no roots when you lift it out, you have grubs. You can also tell if you have grubs if you notice any irregularly shaped dead patches on a well-irrigated lawn appear.
You can expect to see the signs of this during the late summer or early fall when the baby grubs start to get to work! These tests are easy to carry out and will identify any grubs in your lawn.