What do grubs primarily feed on?

Grubs primarily feed on plant roots, which makes them significant pests in many agricultural and garden settings. As the larval stage of certain beetles, grubs thrive underground, where they can access the roots of grasses and other plants. This feeding habit can lead to severe damage; as grubs consume the roots, they disrupt the plant's ability to absorb water and nutrients, potentially leading to plant stress or death.

The other options, such as leaves, fruit, or flower petals, do not align with the feeding habits of true grubs. Leaves might be consumed by different types of pests, while fruit and flower petals could attract other types of insects, but not grubs specifically. Thus, the primary diet of grubs distinctly involves plant roots, which is crucial to understanding their impact on plant health.