WSU Extension

Hortsense

Kinnikinnick : Rust
(revision date: 4/23/2014)


Biology
Kinnikinnick rust is a fungal disease of the leaves which requires an alternate host (spruce) to complete its life cycle. Symptoms of rust on kinnikinnick are seen in late spring, when the undersides of leaves develop an orange to brownish powdery coating of spores. Severe infections can cause leaves to drop. This rust fungus also causes a broom rust of spruce. Infected spruce trees develop large golden yellow witches'-brooms which may reach up to two yards in height.
Management Options

Non-Chemical Management
  • Remove infected spruces from vicinity of desired kinnikinnick plantings, and vice versa.
  • Pick off and destroy (do not compost) infected leaves when practical.
  • Rake and destroy fallen leaves under infected plants.
  • Avoid overhead watering. As with many fungal diseases, rust infection is favored by moisture on the leaves.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

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Caption: Rust on serviceberry
Photo by: R.S. Byther