I've posted several times in this thread regarding Bt. I'm amazed that no one has read those posts.
Bacillus thurengiensis is NON TOXIC, because the active ingredient specifically attacks only the caterpillars of butterflies and moths. NOTHING ELSE.
There ARE other strains of Bt that attack mosquitos(dunks), and others may be in development for other insects.
Bt is one of the oldest organic pesticides and I've told hundreds of gardeners(actually tens of thousands if you include a previous incarnation as a paid organic gardening adviser at a 90's chat site.), and never had a complaint.
In California there is no better alternative to Bt.
Begin spraying now, and continue applications every three weeks until a month before harvest.
If you are still seeing a lot of Fiery Skipper butterflies, consider spraying the leaves and buds with a very fine mist that won't penetrate the buds.
Give the buds a good bath a few hours before harvest to minimize any traces of the spray, bird shit and dust.
Take a good look at the picture linked below. THIS is the source of bud worms!
http://www.genehanson.com/photos/butterfly/fiery_skipper_9086.jpg