grubs

Grubs are the common name for the larval stage of several beetle species, most notably scarab beetles in the family Scarabaeidae. They are typically white or cream-colored, with a brown head and a plump, C-shaped body. Grubs live in soil and feed mainly on plant roots, which can weaken or kill plants when populations are high.

In appearance and development, grubs have three pairs of legs near the front of the body and a smooth, curved abdomen. They hatch from eggs laid by adult beetles in the soil and pass through multiple larval instars before entering a pupal stage. Depending on species and climate, the life cycle may be completed in one year or extend over more than one year.

Ecology and impact vary by context. In lawns and turf, grubs feed on grass roots, causing yellowing, thinning, and turf that can be easily lifted from the soil. In orchard or field settings, they can damage a range of roots, reducing vigor and yields. Natural enemies, including birds and predatory insects, help suppress populations, and certain biological controls such as parasitic nematodes are used in management programs. Some regions employ disease-based controls, such as milky-spore for specific Japanese beetle populations.

Management is typically integrated and site-specific. Practices focus on maintaining healthy turf, monitoring grub levels, and applying controls only when damage risk meets threshold. Biological controls are preferred where feasible, while chemical insecticides may be used when monitoring indicates problematic populations, with attention to timing to target grubs when they are near the soil surface.