If you are out working on your lawn you will often see small grubs. They tend to be curved and white with a little bit of orange at the head end. Their legs are also all up at that end
These are the larvae of a few species of beetle including the Japanese beetle. They can do a lot of damage to your lawn because they eat the roots of the grass.
A safe way to control them is to spread milky spore which is a bacteria. It absorbs into the ground and the grubs will eat the spores and die. It does take time but it will work. You could also use nematodes. Be sure to get the proper type of nematodes because not all are effective against grubs.
Grubs are something that take a little bit more work to get rid of. Make sure that you keep an eye out for them and use the proper natural or chemical controls. They will not damage the soil so you can simply replant your lawn again.