On the lower leaf surface, yellow to orange spore pustules (uredia) surrounded by dark rings occur. The disease generally has little impact on yield but may cause premature defoliation.

Airborne spores produced on hemlock needles infect blueberry leaves in early summer. Yellow spores then develop in uredia on blueberry leaves and spread the disease among blueberries. The fungus overwinters in infected leaves and reinfects hemlock needles in early spring. In the southeastern United States where hemlocks are not present, the fungus overwinters in uredia on evergreen blueberry leaves.

Management
Remove hemlock trees within a third of a mile (0.5 km); avoid susceptible cultivars; limit overhead irrigation; apply effective fungicides.