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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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Mechanical Damage
Photo by Chal Landgren, OSU.
Causes
Equipment and tools
Signs & Symptoms
Broken lower branches and areas of dead foliage where tires and equipment have run over or forced branches apart
Bark/trunk damage (trees on row ends) that looks like cankers with dead branches above the damaged area
Damaged foliage at a consistent height and side on rows where equipment has passed and exhaust fumes or heat have caused injury
Split branch ends from dull shearing knives or cutting tools that do not cut cleanly. Branch ends to shatter and die.
Where to Look
Trees at row ends
Lower branches; branches at equipment level
Similar Symptoms As
Vertebrate damage
Drought
Management Options
Lay out field to leave enough space on row ends and between rows to allow for tractor turns and passage next to full-grown trees.
Shield tractor tires and equipment to allow for passage between the rows.
Minimize trips through the rows during bud break, as new growth is easily broken.
Prevent prolonged contact of foliage with exhaust.
Maintain sharp shearing and cutting tools to ensure well-cut branch ends.
Use basal pruning, which can minimize lower branch damage.
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
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