Root and Crown Rots
Hosts: All conifers
Pathogens: Assorted root rot fungi/water molds.
Signs/Symptoms:  Poor growth, branch dieback, discolored and deteriorated roots
For more information see: UW Plant Disease Facts D0094

Rhizosphaera Needle Cast
Hosts: Colorado blue spruce, other spruces, other conifers
Pathogen: Rhizosphaera kalkhoffii
Signs/Symptoms:  Browning/purpling of interior needles of lower branches, followed by needle drop
For more information see: UW Plant Disease Facts D0093

Cytospora Canker
Hosts: Colorado blue spruce, other spruces
Pathogen: Cytospora kunzei
Signs/Symptoms:  Branch dieback with milky-white patches of dried sap on affected branches
For more information see: UW Plant Disease Facts D0033

Spruce Needle Drop
Hosts: Spruces
Pathogen: Unknown (thought possibly to be Setomelannoma holmii)
Signs/Symptoms:  Needle loss and dieback at or near branch tips

Gymnosporangium Rusts
Hosts: Junipers, apple, crabapple, hawthorn, quince
Pathogen: Gymnosporangium spp.
Signs/Symptoms:  Brown blobs with orange gelatinous masses (juniper); yellow/orange leaf spots (other hosts)
For more information see: UW Plant Disease Facts D0058

Phomopsis Tip Blight
Hosts: Junipers
Pathogen: Phomopsis juniperovora
Signs/Symptoms:  Browning and dieback of branch tips in spring and early summer as new growth emerges
For more information see: UW Plant Disease Facts D0077

Diplodia Shoot Blight and Canker
Hosts: Austrian pone, other pines
Pathogen: Diplodia spp.
Signs/Symptoms:  Dieback of branch tips with dead needles showing uneven lengths
For more information see: UW Plant Disease Facts D0042

Dothistroma Needle Blight
Hosts: Austrian pine, other pines
Pathogen: Dothistroma pini
Signs/Symptoms:  Needle tip browning and death with a distinct break between live and dead tissue
For more information see: UW Plant Disease Facts D0043

Drought Stress
Hosts: All conifers
Cause: Insufficient water
Signs/Symptoms:  Purpling/browning of needles near branch tips or higher up in plants during the summer

Winter Injury
Hosts: All conifers, particularly yews and junipers
Cause: Insufficient water
Signs/Symptoms:  Needle browning/bleaching over winter or in spring as plants come out of dormancy
For more information see: UW Plant Disease Facts D0127

Herbicide Damage
Hosts: All conifers
Cause: Exposure to herbicides
Signs/Symptoms:  Twisted or otherwise distorted growth, needle yellowing or browning, plant death
For more information see: UW Plant Disease Facts D0060