The home side moved into an 18-4 lead at the break as Jamie Foster converted two Keith Lulia tries, as well as an additional score from Brett Kearney. Meanwhile, Mathias Pala touched down for the visitors.
The Dragons came out fighting at the start of the second period and were rewarded when Jamal Fakir went over on 42 minutes, allowing Bosc to add the extras.
Bosc kicked over Brent Webb's try with 20 minutes left to bring the visitors to within two points of their opponents, but Bradford went further ahead through an Adrian Purtell score on 68 minutes.
However, Ian Henderson went over in the final stages before Bosc's drop goal sealed the win.