Larvae of beetles, such as Japanese beetles or June bugs, are commonly known as white grubs. They spend their immature stage buried in the soil where they consume grass roots. This feeding activity weakens the turf, causing patches of grass to yellow, thin, or die. The lawn may feel spongy, and the affected sod can be rolled back easily like a loose mat. The presence of these pests leads to a second problem: nocturnal mammals that consider the grubs a high-protein food source. These animals actively dig up lawns at night, turning a subtle grub infestation into a noticeable, destructive mess.
Identifying the Nocturnal Grub Eaters
The majority of grub-related lawn damage is caused by three primary nocturnal omnivores: skunks, raccoons, and opossums. All are attracted to the protein-rich larvae. A strong sense of smell allows these animals to locate their prey even when the grubs are several inches below the surface. Grubs are an appealing target in late summer and fall, when the larvae are at their largest and the animals are focused on accumulating fat reserves for the winter.
Skunks are adept at foraging for grubs, relying on their keen sense of smell to pinpoint individual larvae. They use their strong front claws and snout to dig small, conical holes, systematically working across an infested area. Skunk digging is localized where grubs are most concentrated. The holes are typically shallow, often no larger than the skunk’s nose.
Raccoons use their highly dexterous front paws to employ a different, more destructive hunting method. They prefer to peel back or roll up sections of loosened sod to expose the grubs underneath. This behavior results in larger, more extensive areas of damage. The lawn may look as though someone intentionally ripped and rolled back pieces of carpet.
Opossums are also attracted to grubs, but they are generally less destructive than raccoons or skunks. The opossum has delicate feet and nails, causing it to avoid extensive digging unless the grubs are very near the surface. They may leave behind small, shallow excavations. Their damage is often messier and less defined than the distinct holes left by a skunk.
Recognizing the Signs of Predation
Distinguishing between the nocturnal culprits comes down to the specific pattern and depth of the damage left on the lawn. Skunk predation is characterized by numerous small, cone-shaped holes, typically 3 to 4 inches in diameter. These holes appear as if someone repeatedly pressed a dowel or ice pick into the ground. They are created by the skunk’s nose-diving action and are often scattered across the lawn in a searching pattern.
Raccoon damage is more dramatic, involving the lifting and tearing of the turf itself. This leaves behind large, irregularly shaped patches of sod that are either flipped over or ripped out. The animal uses its paws like hands, grabbing and peeling the grass away from the root base weakened by the grubs. Opossum damage is generally less severe, presenting as shallow, small, and messy depressions where the animal briefly foraged. This damage lacks the depth of a skunk hole or the widespread tearing of a raccoon.
Managing Wildlife Interactions
The most effective long-term strategy for stopping nocturnal animals from damaging a lawn is to eliminate their primary food source: the grubs. A significant grub population, often five or more per square foot, is enough to attract skunks and raccoons. Removing the underlying infestation with targeted treatments, such as applying beneficial nematodes or insecticides, removes the incentive for the animals to dig.
While waiting for grub control measures to take effect, homeowners can use temporary deterrents. Non-lethal exclusion methods are often successful, including laying chicken wire or bird netting flat across the damaged area and securing it with landscape staples. Motion-activated sprinklers or lights can also frighten away animals sensitive to sudden changes. Removing other attractants, such as fallen fruit, pet food left outside, or unsecured garbage, helps make the yard less appealing to foraging wildlife.