Plan the perfect garden with our interactive tool →

Diseases of the Colorado Blue Spruce

Colorado blue spruce trees are evergreens discovered growing on the sides of the Rocky Mountains in 1862. Their beauty and color quickly made them a favorite tree. Blue spruce is a hardy tree type that has few problems with disease. But when they do become diseased, it decreases their value and reduces their ability to act as a wind break.

Tree Identification

Blue spruce trees make beautiful Christmas trees and are used as wind breaks and ornamental landscape. The trees grow well is zones 2-8 if they are planted in a sunny location. Full-grown healthy trees can reach 75 feet in height. Birds and small animals nest in blue spruce's full, branching foliage.

  • Colorado blue spruce trees are evergreens discovered growing on the sides of the Rocky Mountains in 1862.
  • The trees grow well is zones 2-8 if they are planted in a sunny location.

Needle Blight Diseases

Lirula and Rhizosphaera are needle blight diseases occurring in blue spruce trees.

Lirula macrospore fungus infects the trees during the warm summer months. The needles show yellow bands that turn purplish brown about 17 months after infection. Black spore bodies that are smooth in texture develop on the needles about 23 months after infection. Needles become light in color and drop from the tree. Control requires two applications of fungicide for three years after the start of infection.

Rhizosphaera kalkoffi fungus infects trees in late spring through early summer. The needles turn yellow followed by purplish brown in winter following infection. Black fuzzy spore bodies develop along the needles a year after infection. The needles start falling off the trees shortly after spore development. Rhizosphaera is controlled with an application of fungicide twice a year for two years.

  • Lirula and Rhizosphaera are needle blight diseases occurring in blue spruce trees.
  • Black spore bodies that are smooth in texture develop on the needles about 23 months after infection.

Canker Disease

Cytospora canker fungus infects blue spruce trees through wounds in the branches. The spores spread by means of rain drops, animals and pruning tools. Once infected, the lower branches of the tree turn brown, which results in needle loss. Infected branches display cankers that are covered with white-blue colored sap. Control of the disease includes limiting the number of wounds while pruning and cleaning tools between each cut. Remove and destroy infected branches over a two-year period to reduce the spread of the fungus.

Vulnerability

Dirty and infected pruning tools spread disease to healthy trees. Disinfect the tools between each cut by dipping into alcohol for three minutes. Sterilize tools after use by cleaning with a solution of one part bleach to nine parts water. Reduce environmental damage to trees to decrease the risk of a disease. This includes compacted soil, drought conditions and excessive temperatures.

  • Cytospora canker fungus infects blue spruce trees through wounds in the branches.
  • Control of the disease includes limiting the number of wounds while pruning and cleaning tools between each cut.

Prevention

Prune healthy trees first to prevent spreading disease spores. Inspect new stock for spore bodies before planting to eliminate the introduction of unhealthy trees to healthy trees. Prune during dry seasons to prevent the spread of spores. Space trees when planting to improve air circulation and decrease moisture build up.

Related Articles

Why Are My Evergreen Trees Turning Brown?
Why Are My Evergreen Trees Turning Brown?
Blue Atlas Cedar Disease
Blue Atlas Cedar Disease
How to Care for Monkey-Puzzle Trees
How to Care for Monkey-Puzzle Trees
Insects on Juniper Trees
Insects on Juniper Trees
Why Are My Pine Trees Dying?
Why Are My Pine Trees Dying?
Evergreen Tree Identification
Evergreen Tree Identification
Hinoki Cypress Diseases
Hinoki Cypress Diseases
Fast Growing Trees in the Pacific Northwest
Fast Growing Trees in the Pacific Northwest
Why Is My Blue Spruce Turning Red & Losing Its Needles?
Why Is My Blue Spruce Turning Red & Losing Its Needles?
Diseases of Bradford Pear Trees
Diseases of Bradford Pear Trees
Trees & Rust Fungus
Trees & Rust Fungus
Female vs. Male Chinese Pistachio
Female vs. Male Chinese Pistachio
Black Hills Spruce Facts
Black Hills Spruce Facts
Fungicide to Treat Blue Mold in Pine Trees
Fungicide to Treat Blue Mold in Pine Trees
Loblolly Pine Tree Diseases
Loblolly Pine Tree Diseases
Bugs That Live in Pine Trees
Bugs That Live in Pine Trees
Pine Tree Needle Diseases
Pine Tree Needle Diseases
Diseases of a Sweet Gum Tree
Diseases of a Sweet Gum Tree
Cleveland Pear Tree Diseases
Cleveland Pear Tree Diseases
Garden Guides
×