There is a product called Oxidate that can be used as a spot treatment for molds including budrot. All outdoor growers should have this in their arsenal.
Good luck in harvest
Thats bad advise. Oxidate will ruin your buds and is only for Powdery mildew not the wood rot types of mold we deal with later in flower.
I live within Zone 17, which is the foggy lettuce belt. I actually am 2 minutes from the ocean, so I do feel your pain. The Larger garden I work at has a great view of the big ol' pacific. Both places have intense mold problems (My house being worse).
If the bud itself is moldy your going to need to remove it before it continues spreading. Botryis and other wood rots like to really focus the stem, in my experince it will develop on the stem, Ill harvest and then I can run my finger along the stem and easily wipe off all the bud cleanly from the steam in a moldy goup. None the less the bud looked PERFECT on the outside. Keep your eyes open, dont be afraid to get into your buds when your trimming them. Botryis really stops spreading after you remove it from the plant and it doesnt have something to feed off.
Now if you face this on the stem there are ways to fight it without having to remove the branch. Take your pocket knife out, start scraping away the mold and affected tissue (Dont go to deep, I may go take pictures of this process for you). Then I just nuke it with 91% Iso alchohol. Now to much of the alchohol (Two weeks of treatment) will kill the branch by drying it out. I try to treat every couple days and it really helps keep the mold back.
Also something we have started doing is making hash oil with your moldy bud. Really helps when you plan to loose half your harvest...
Chobble