What do large white grubs turn into?
Considering this, what does a white grub turn into?
Lawn Grubs, often called White Grubs, are the immature form of different Scarab Beetles, such as Japanese Beetles, June "bugs" (beetles) or the European Chafers. Grubs eventually turn into adult Beetles and emerge from soil to mate and lay eggs, which hatch into more Grubs.
Similarly, you may ask, what are the big white grubs in my compost?
If you have ventured into making your own compost, undoubtedly sooner or later you've discovered large, C-shaped white grubs in the compost pile. They're most likely the larvae of a green June beetle (Cotinus spp.), although the bumble flower beetle (Euphoria inda) also lives in compost. They help process your compost.
The answer is no. White grubs present in lawns (and many of those in garden beds) are almost always one of two species of scarab beetle known as the June beetle and the masked chafer. Both species can be damaging to turf in late summer, though feeding during the winter and spring is insignificant.