In their book, Green Thumb Wisdom: Garden Myths Revealed!, Doc & Kay Abraham tell us toads are valuable bug killers. An entomologist figured that a single toad is worth $200 to $300 in bug control today. Toads eat all kinds of injurious beetles, sowbugs, slugs and snails, potato beetles, grasshoppers, caterpillars, armyworms, wireworms, and gypsy moths. About 80 percent of the otad's diet consists of pest insects. One lone toad will eat tens of thousands of insects a year.