I've been nailed by this stuff bad. Last year it was just a small problem infecting just a few plants.This year it is devastating a majority of the crop.It only shows up when flowering begins and it causes the older parts of the bud to dye and shrivel.while the new bud continues to grow and dye on top.I hope someone finds the answer for as I have written off my entire season this year I would like to find a preventative measure for next.I am certain it is not genetic.I have had issues with cutworms inside the stems(this could be the viral carrier that harddon refered to).