Grub Worms

Behavior and Habitat of Grub Worms

Grubs are voracious feeders, and in most cases are the larvae of Japanese beetles, annual white grubs, or green June beetles. After the beetles mate during late spring/early summer, the females lay eggs in the soil. Once the eggs hatch, the grubs feed in the soil during the warm days of summer. As the soil temperature begins to fall, they burrow deeper to spend the winter, sometimes to depths of 4 or 5 feet below ground. Depending on the weather, they may be higher or lower in the soil when spring arrives. Then they will be back up near the surface and feeding on grass roots again. White grubs eat organic matter, including the roots of plants. Therefore, damage first appears to be drought stress. Heavily infested turf appears as an off color, gray-green, and wilts rapidly in the hot sun. Continued feeding will cause the turf to die in large irregular patches. The tunneling of the larvae cause the turf to feel spongy under foot and the turf can often be rolled back like a loose carpet.