Do cicadas eat the tomato plant or just tomato?

Cicadas do neither. Cicadas are insects that belong to the order Hemiptera, which also includes aphids, leafhoppers, and planthoppers. Cicadas are known for their periodic emergences, during which large numbers of adults appear above ground to mate and lay eggs. Adult cicadas do not feed, and they do not cause damage to plants. Some cicada species, however, can cause damage to trees by laying their eggs in the twigs, which can cause the twigs to break.