What Are White Grubs?
White grubs are the larvae of certain beetles that live in the soil and feed on the roots of turfgrass. This root feeding can cause noticeable lawn damage. The grubs are white, about 1 inch long, with brown heads, small legs, and faint stripes on their backs. They also have bristles underneath and a slight narrowing near the front of the abdomen, which helps in identification.
In California, the most common species are Cyclocephala hirta (widespread) and C. pasadenae (mostly in Southern California). These grubs spend the winter underground as mature larvae, then turn into beetles in the soil. The adult beetles usually come out at night from mid-June to July and are attracted to lights.
Signs of Grub Damage
Early signs of grub damage include turf that feels soft or spongy when walked on. In advanced cases, the grass can be pulled up easily, like a carpet, due to extensive root feeding.
You may also notice patches of lawn that wilt or turn brown despite adequate watering.
Damage tends to peak in late summer or early fall. One of the most noticeable indicators is increased digging activity by animals like crows, raccoons, skunks, or coyotes searching for grubs beneath the surface.
Grub Treatment & Prevention
Preventing and managing grub infestations starts with a combination of proper lawn care and timely treatment. In addition to applying recommended treatments, maintaining healthy lawn care practices is one of the most effective ways to protect against grubs and other pests. Consistent watering, fertilization, aeration, and controlling thatch buildup are essential to keeping turf strong and resilient.
Preventive treatments consists of a foliar spray or drench applied to grass blades, along with a soil drench to reach developing grubs below the surface. These applications will help treat for any current grub larvae and stop further root damage. For best results, preventive treatments should be applied in late spring to early summer—when beetles are laying eggs but before grubs begin to cause visible harm. Damaging grub populations usually become noticeable later in the season, from late summer through the following spring, after they’ve fed extensively on grass roots.
