Grubs eventually turn into adult Beetles and emerge from soil to mate and lay eggs, which hatch into more Grubs. Most Scarab Beetles have a one-year life cycle; June Beetles have a three-year cycle.Click to see full answer. Simply so, do june bugs make grub worms?White grub worms are the larvae of various scarab beetles, including June bugs, Japanese beetles, dung beetles and northern masked chafers. Green June beetle larvae are the exception, they have no developed legs. White grubs reach up to 1 inch long, depending on their age and species.Also, what do june bugs turn into? The name June bug actually refers to around 300 different species of beetle within the genus Phyllophaga. Their life cycle is as follows: egg » larva » pupa » adult. Adults lay eggs in May and June, which hatch two and a half weeks later into small white larva, also known as grubs. Also know, how long does it take for a grub to turn into a beetle? about 12 months What is the life cycle of a grub worm?White grub species all complete their life cycle in 1 year, with the exception of the June Beetle, which has a 3 year life cycle. Adult beetles dig shallow holes in the soil where they lay their eggs. Depending on the particular white grub species, the egg laying period occurs between June and August.