Naohidemyces vaccinii is a plant pathogen that affects members of the Vaccinium and Tsuga genera, causing leaf rust on lingonberries, blueberries, and cranberries, and early needle cast on hemlocks.

Teliospores germinate from telia in spring, from which basidia form, releasing basidiospores to Tsuga species.

It is a relatively benign disease, and has little direct impact on crops, but has become an epidemic in rare occasions, particularly to cultivated blueberries.

Applications depend on climate and species, as Vaccinium that keep their leaves throughout the year may need to be treated far earlier than the first sign of leafing out.

[5]  Removing Tsuga or other wild, evergreen Vaccinium hosts within 0.5 km of crops can be beneficial in breaking the sporulation cycle.