A 19-year-old man was arrested in Castroville yesterday, after C-H-P officers allegedly found a small, home-made bomb in his vehicle. Officers were conducting a traffic stop on Seaside resident Daniel Walter Diamond, when they searched his vehicle after smelling marijuana. No drugs were found, but a device described as a home-made tennis ball bomb was discovered. Bomb-squad officers were called to render the device safe, and Diamond was booked into Monterey county jail on suspicion of possession of a destructive device.