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C-shaped white grub laying on recently-dug soil
Those jaws are made for chomping roots. Photo: NYSIPM. Click photo to see enlarged version.

Introduction

A white grub is the immature (larval) form of a scarab beetle. In NY, these include four native species (black turfgrass ataenius, green June beetle, May or June beetles, northern masked chafer) and four introduced species (Asiatic garden beetle, European chafer, Japanese beetle, Oriental beetle).

Grubs live in the soil, feeding on plant roots, so you may not be aware of them until you see damage. While the adults of some species feed on and are damaging to ornamental plants (e.g., Japanese beetle, Asiatic garden beetle), the adults of other species may not feed at all (e.g., European chafer). No adults feed directly on turfgrass.

A Grub’s Life: Egg to Beetle

Knowing the life cycle of grubs is the key to determining whether you have a problem, what to do about it, and when to do it. By considering a grub’s life cycle, you can anticipate problems before your lawn is ruined—not just by root damage, but by hungry birds and rodents as well. The biology of the Japanese beetle is typical of most grubs encountered in New York State and is illustrated below.

illustration showing the life cycle of a Japanese beetle from grub to pupae to adult from June to July, Adult to egg to larvae getting bigger from July to October, largest grubs deeper in soil profile November to May, then grub towards soil surface May to June

What Do White Grubs Look Like?

Why Should I Worry About White Grubs?

How Do I Know If I Have White Grubs?

How Do I Manage White Grubs in Turfgrass?