Baby grasshoppers, called "nymphs," eat young, tender vegetation such as clover, grass and fresh shoots. Adult grasshoppers prefer plants in the grass family such as corn, wheat, alfalfa and barley.
Grasshoppers eat almost any plant. They are not picky and even eat the leaves on a tree. Special chemicals in the insect's saliva and stomach break down the roughage so their bodies can extract and use the carbohydrates within. Grasshoppers in captivity eat almost any type of vegetation, including lettuce, vegetables, grass and leaves. In response to certain environmental stimuli, grasshoppers grow larger and begin to swarm as locusts, devouring hundreds of miles of vegetation at a time.