What are the beetle larvae that overwinter in the soil and attack plant roots called?

The term used for beetle larvae that overwinter in the soil and have a tendency to attack plant roots is "grubs." Grubs are the larval stage of various beetle species and are typically characterized by their C-shaped bodies. They are commonly found in soil, where they feed on organic matter and plant roots, potentially causing significant damage to crops and lawn plants. Overwintering is a behavior seen in grubs, allowing them to survive through colder climates in the soil until conditions are favorable for emergence and feeding.

Worms, while they play a crucial role in soil health and plant growth, are not beetle larvae. Caterpillars are the larvae of moths and butterflies and do not have the same developmental stage as grubs. The term larvae is broad and can refer to any immature form of an insect, not specifically those associated with beetles or the characteristics that define grubs. Thus, "grubs" is the precise and accurate term for this specific context.