fruit flies are tiny insects tat are attracted to ripe or rotting fruits and vegetables. the flies not only eat the fruit, they also lay their eggs there. a single fruit fly can lay up to 500 eggs on the surface of a piece of fruit. within eight days, the fruit flies that hatch from these eggs are full adults that can then lay their own eggs. as you can see, what might start out as a small fruit fly problem can become very large very large very quickly.