See:
Blueberry (Vaccinium corymbosum)-Rust
Huckleberry (Vaccinium spp.) - Witches' Broom Rust
Notes The fungus Naohidemyces vaccinii has been reported on the deciduous huckleberry (Vaccinium membranaceum) from all PNW states, ever-green huckleberry (V. ovatum) WA, dwarf bilberry (V. caespitosum) OR and WA, Alaska blueberry (V. ovalifolium) OR and WA, little leaf huckleberry (V. scoparium) OR and ID. Hemlock (western or Pacific hemlock, Tsuga heterophylla, and the mountain or black hemlock, T. mertensiana) are the alternate hosts. Remove upwind hemlocks and prompt removal and disposal of fallen leaves may be helpful. Specific fungicide timing is not known but it is suggested to start when leaves first begin to break bud and unfold.