Whats killing my branches???

[Mendojuana]

I'll notice a brown spot on a limb,in two days its an inch long and all the growth above it is dead??? When I cut the dead branch off the brown stuff is like dust,is this dust spores and will they infect another branch they land on??? Mendo........

 

[Verve]

I'll notice a brown spot on a limb,in two days its an inch long and all the growth above it is dead??? When I cut the dead branch off the brown stuff is like dust,is this dust spores and will they infect another branch they land on??? Mendo........

I just had the exact same problem, there called stem cankers. Cut off all infected branches like right now i spreads quick as you have probaly already seen. I use defender fungicide to prevent it from atacking the othere and it worked great.