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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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Heat Damage
Photo by Chal Landgren, OSU.
Causes
Photo by Chal Landgren, OSU.
Extreme high temperatures and/or intense sunlight
Signs & Symptoms
Photo by Chal Landgren, OSU.
Groups of needles on a shoot quickly turn reddish-brown.
Entire tree appears burned/reddened due to late-season high temperatures that damage needles and shoots.
Heat, drought, and sunscald damage are closely related.
Where to Look
South or southwest side of the trees
Similar Symptoms As
Current season needle necrosis
Mechanical damage
Chemical injury
Management Options
Protect young seedlings using shade devices, such as shingles and cards.
In older plantings, try to maximize soil moisture levels.
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