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Spruce
Disease
Oil discoloration of foliage
Rhizosphaera needle cast
Rust
Insect
Coneworms
Cooley spruce gall adelgid
Douglas fir tussock moth
Pine needle scale
Spruce aphid
Spruce bud scale
Spruce budworm
Spruce needleminer
Spruce spider mite
White pine weevil
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Caption: Spruce rust
Photo by: R.S. Byther
Spruce : Rust
(revision date: 4/23/2014)
Use Integrated Pest Management (IPM) for successful plant problem management.
Biology
Spruce rusts are fungal diseases that sometimes require an alternate host to complete their life cycle. There are many rust diseases of spruce, each with different alternate hosts. One spruce rust causes witches' brooms, or abnormally bushy growth of the branches. These witches' brooms gradually lose their healthy green color and turn yellowish or brownish as the fungus matures. Kinnikinnick is the alternate host.
Management Options
Non-Chemical Management
Remove alternate hosts (when known) from around spruce plantings.
Prune and destroy witches' brooms where possible.
Select non-chemical management options as your first choice!
Chemical Management
IMPORTANT:
Visit Home and Garden Fact Sheets for more information on using pesticides
None recommended
Images
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Caption: Spruce rust
Photo by: R.S. Byther
Caption: Spruce rust: witches' broom
Photo by: R.S. Byther