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Oregon State University
College of Agricultral Sciences
OSU Extension Service
OSU Extension Catalog
Identifying and Managing Christmas Tree Diseases, Pests, and Other Problems
Diseases
Annosus Root Rot
Phytopthora Root Rot
Grovesiella Canker
Interior Needle Blight
Rhabdocline Needle Cast
Swiss Needle Cast
Melampsora Needle Rust
Pucciniastrum Needle Rust
Uredinopsis Needle Rust
Insects
Twig Aphid
Conifer Root Aphid
Conifer Aphids
Balsam Wooly Adelgid
Cooley Spruce Gall Adelgid
Douglas-fir Needle Midge
Spruce Spider Mite
Eriophyid Mites
Root Weevil
Douglas-fir Twig Weevil
Disorders
Interior Needle Loss
Yellow-green Mottle Syndrome
Current Season Needle Necrosis (CSNN)
Damage
Weather Damage
Frost Damage
Winter Injury
Drought
Heat Damage
Chemical Damage
2, 4-D and Triclopyr
Fertilizer Burn
Glyphosate (Roundup)
Triazines
Vertebrate Damage
Deer, Elk, Mice & Voles
Rabbits & Birds
Mechanical Damage
Mechanical Damage
About
Authors & Acknowledgments
Copyright and Disclaimer
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Phytopthora Root Rot
Phytophthora
spp
Photo by Chal Landgren, OSU.
Signs & Symptoms
Photo by Chal Landgren, OSU.
Reduced or stunted growth
Poor color
Root decay
Bleeding basal cankers
Dead branches first noticeable at the base of the tree
Where to Look
Photo by Chal Landgren, OSU.
Low-lying areas with poor drainage
Similar Symptoms As
Photo by Chal Landgren, OSU.
Other root diseases
Drought
Scouting
Cut the tree and check cambium for presence of canker.
Dig roots and check for dark and rotten roots.
Look for dead trees in field.
Look for flagging branches.
Management Options
Replant with resistant species.
Improve field drainage (e.g., tiling, ditches).
Avoid sites with poorly drained soils.
Host Susceptibility
View text version
High susceptibility: Fraser fir, Noble fir, Shasta fir
Medium susceptibility: Douglas-fir
Low susceptibility: Grand fir, Nordmann fir, Turkish fir
Management Calendar
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Look for dying, yellowing trees; trees with cankers: April through Mid-September
Scout for especially off-color trees with dead branches and wet areas: April through Mid-September
Plant resistant species: February through March
Improve drainage: September through October
Diseases
Annosus Root Rot
Phytopthora Root Rot
Grovesiella Canker
Interior Needle Blight
Rhabdocline Needle Cast
Swiss Needle Cast
Melampsora Needle Rust
Pucciniastrum Needle Rust
Uredinopsis Needle Rust
OSU Extension Publications
OSU Extension Catalog
Best Management Practices for Christmas Tree Export
Buenas Prácticas de Manejo para la Exportación de Árboles de Navidad
Identifying and Managing Christmas Tree Diseases, Pests, and Other Problems
Identificación y Manejo de Enfermedades, Plagas y Otros Problemas en Árboles de Navidad
Identifying and Managing Christmas Tree Diseases, Pests, and Other Problems
Diseases
Annosus Root Rot
Phytopthora Root Rot
Grovesiella Canker
Interior Needle Blight
Rhabdocline Needle Cast
Swiss Needle Cast
Melampsora Needle Rust
Pucciniastrum Needle Rust
Uredinopsis Needle Rust
Insects
Twig Aphid
Conifer Root Aphid
Conifer Aphids
Balsam Wooly Adelgid
Cooley Spruce Gall Adelgid
Douglas-fir Needle Midge
Spruce Spider Mite
Eriophyid Mites
Root Weevil
Douglas-fir Twig Weevil
Disorders
Interior Needle Loss
Yellow-green Mottle Syndrome
Current Season Needle Necrosis (CSNN)
Damage
Weather Damage
Frost Damage
Winter Injury
Drought
Heat Damage
Chemical Damage
2, 4-D and Triclopyr
Fertilizer Burn
Glyphosate (Roundup)
Triazines
Vertebrate Damage
Deer, Elk, Mice & Voles
Rabbits & Birds
Mechanical Damage
Mechanical Damage
About
Authors & Acknowledgments
Copyright and Disclaimer
Order
Order Publication