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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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Drought
Photo by Chal Landgren, OSU.
Causes
Depleted soil moisture that lasts into the fall
Late season planting that compromises root growth
Signs & Symptoms
Wilting of new growth, top dieback, tree death
Loss of interior needles, shortened needles, needle tip dieback, and overall slow growth
Symptoms generally start at the top of the tree and continue downward.
Damage may occur over several years
Where to Look
Newly planted trees
Plants growing on gravelly or sandy soils
Similar Symptoms As
Root problems
Winter damage
Management Options
To conserve water, eliminate competing vegetation with weed and brush control.
Assess the type of soil where trees are going to be planted.
Plant drought-tolerant species.
Supplement irrigation as a last resort.
Closely monitor trees weakened by drought because they are prone to other problems, especially insects and diseases.
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