Grubs are larvae.
They come from a variety of different beetles, including Asiatic, Japanese, May and June beetles. In late August and early September, the lawn grass will turn brown. There will be large patches of discoloration, irregularly shaped, which roll easily like a carpet. They have brown heads, three pair of legs and lie curled in the soil. When the eggs hatch, grubs feed down 1 to 3 inches in the soil on grass roots.