Treatment for White Pine - Ask Extension
Can you help me diagnose and come up with a treatment plan for the attached white pine? I have several that look similar to this. An arborist told ...
Knowledgebase
Treatment for White Pine #852918
Asked October 12, 2023, 8:44 AM EDT
Can you help me diagnose and come up with a treatment plan for the attached white pine? I have several that look similar to this. An arborist told me they were planted too deep, which I’ve since corrected. Could it be blister rust? White pine weevil? Should I prune the dark brown branches?
Kent County Michigan
Expert Response
Hello,
According to Michigan State University Extension, pine needles turning brown and dropping can be caused by infection, weather conditions, insects, spider mite feeding, needlecast diseases, nutrient deficiency, or stress. If the needles are turning brown in spring, it could be due to the cold, dry winter, and wind exposure. If the change in color and drop is happening in late summer or fall, it could be a physiological response to the shorter days and cooler nights as trees prepare for winter. Dothistroma needle blight is a common pine pathogen that can cause browning of needles.
Minor needle browning or dieback usually requires no pruning because the needles quickly drop on their own. If the unsightly needles persist or an entire branch browns, proper pruning can solve the problem—Disinfect pruning shears and saws in a solution of one bleach to nine parts of water before cutting. Removing dead branches reduces the risk of tree rot, invasive pest insects, and spreading tree diseases.
It is important to note that once a branch or needle has completely turned brown, it will never revert to its healthy state. In some cases, however, you may be able to diagnose and treat the issue to prevent the spread of the disease.
Check out these articles from Michigan State University Extension at the below information:
Managing Dothistroma and brown needle blight on pines - Jill O'Donnell, Michigan State University Extension, and Jan Byrne, MSU Diagnostic Services, Department of Plant, Soil and Microbial Sciences - June 14, 2013 - Scotch, Austrian, and white pine are susceptible to several needle blights that cause needles to brown, shed prematurely and may eventually kill the tree. At this link:
https://www.canr.msu.edu/news/managing_dothistroma_and_brown_needle_blight_on_pines
Why are my pine trees turning brown? - Jill O'Donnell, Michigan State University Extension and Bert Cregg, Michigan State University Extension, Departments of Horticulture and Forestry - May 17, 2019, at this link:
https://www.canr.msu.edu/news/why_are_my_pine_trees_turning_brown
Fall needle drop: A natural phenomenon in conifers - Mary Wilson, Michigan State University Extension - October 21, 2011, at this link:
https://www.canr.msu.edu/news/fall_needle_drop_a_natural_phenomenon_in_conifers
Why are my interior conifer needles turning yellow? - Jill O'Donnell, Michigan State University Extension, and Bert Cregg, Michigan State University Extension, Departments of Horticulture and Forestry - September 29, 2017, at this link:
https://www.canr.msu.edu/news/yellowing_interior_needles_in_conifers
Here is the information on blister rust - White pine blister rust damage showing up - Jill O'Donnell, Michigan State University Extension, and Jan Byrne, MSU Diagnostic Services - April 28, 2016 - Orange-yellow blisters are a visible sign of white pine blister rust. This fungus can kill branches and even trees. At this link:
https://www.canr.msu.edu/news/white_pine_blister_rust_damage_showing_up
Here is the information on the white pine weevil - Control white pine weevil in early spring - David Lowenstein, Michigan State University, Department of Entomology - March 27, 2023 - Updated from an original article written by Dave Smitley. There is a brief window to manage white pine weevils with insecticides. At this link:
https://www.canr.msu.edu/news/control_white_pine_weevil_in_early_spring
You can also get a confirmed diagnosis from the MSU Diagnostic Plant & Pest Lab - Please email your digital image prior to bringing or sending physical samples. It can be sent to <personal data hidden>.
MAKE SURE IN THAT E-MAIL YOU INCLUDE YOUR NAME, ADDRESS, AND PHONE NUMBER!!
Be prepared. The lab may ask for more images - THE LAB WILL LET YOU KNOW IF A SAMPLE NEEDS TO BE SENT - There is a $20-25 dollar fee (if they need a sample sent).
Lab email: <personal data hidden>
Lab phone:<personal data hidden>
Hours of operation: Monday through Friday, from 8:00 AM to 5:00 PM.
PLEASE READ BELOW ON PREPARING YOUR SAMPLE (if the lab needs a sample)
From the lab: Please do not ship samples on Fridays. They thank you for your patience and understanding.
Every sample must be accompanied by a completed submission form. Please place the form in a separate resealable bag to prevent it from getting damp or soiled. The form is at this link: https://www.canr.msu.edu/pestid/uploads/files/General_Sample_Submission_Form_May2022.pdf.
Complete details of submitting a sample are at this link: https://www.canr.msu.edu/pestid/submit-samples/
I hope this helps!
According to Michigan State University Extension, pine needles turning brown and dropping can be caused by infection, weather conditions, insects, spider mite feeding, needlecast diseases, nutrient deficiency, or stress. If the needles are turning brown in spring, it could be due to the cold, dry winter, and wind exposure. If the change in color and drop is happening in late summer or fall, it could be a physiological response to the shorter days and cooler nights as trees prepare for winter. Dothistroma needle blight is a common pine pathogen that can cause browning of needles.
Minor needle browning or dieback usually requires no pruning because the needles quickly drop on their own. If the unsightly needles persist or an entire branch browns, proper pruning can solve the problem—Disinfect pruning shears and saws in a solution of one bleach to nine parts of water before cutting. Removing dead branches reduces the risk of tree rot, invasive pest insects, and spreading tree diseases.
It is important to note that once a branch or needle has completely turned brown, it will never revert to its healthy state. In some cases, however, you may be able to diagnose and treat the issue to prevent the spread of the disease.
Check out these articles from Michigan State University Extension at the below information:
Managing Dothistroma and brown needle blight on pines - Jill O'Donnell, Michigan State University Extension, and Jan Byrne, MSU Diagnostic Services, Department of Plant, Soil and Microbial Sciences - June 14, 2013 - Scotch, Austrian, and white pine are susceptible to several needle blights that cause needles to brown, shed prematurely and may eventually kill the tree. At this link:
https://www.canr.msu.edu/news/managing_dothistroma_and_brown_needle_blight_on_pines
Why are my pine trees turning brown? - Jill O'Donnell, Michigan State University Extension and Bert Cregg, Michigan State University Extension, Departments of Horticulture and Forestry - May 17, 2019, at this link:
https://www.canr.msu.edu/news/why_are_my_pine_trees_turning_brown
Fall needle drop: A natural phenomenon in conifers - Mary Wilson, Michigan State University Extension - October 21, 2011, at this link:
https://www.canr.msu.edu/news/fall_needle_drop_a_natural_phenomenon_in_conifers
Why are my interior conifer needles turning yellow? - Jill O'Donnell, Michigan State University Extension, and Bert Cregg, Michigan State University Extension, Departments of Horticulture and Forestry - September 29, 2017, at this link:
https://www.canr.msu.edu/news/yellowing_interior_needles_in_conifers
Here is the information on blister rust - White pine blister rust damage showing up - Jill O'Donnell, Michigan State University Extension, and Jan Byrne, MSU Diagnostic Services - April 28, 2016 - Orange-yellow blisters are a visible sign of white pine blister rust. This fungus can kill branches and even trees. At this link:
https://www.canr.msu.edu/news/white_pine_blister_rust_damage_showing_up
Here is the information on the white pine weevil - Control white pine weevil in early spring - David Lowenstein, Michigan State University, Department of Entomology - March 27, 2023 - Updated from an original article written by Dave Smitley. There is a brief window to manage white pine weevils with insecticides. At this link:
https://www.canr.msu.edu/news/control_white_pine_weevil_in_early_spring
You can also get a confirmed diagnosis from the MSU Diagnostic Plant & Pest Lab - Please email your digital image prior to bringing or sending physical samples. It can be sent to <personal data hidden>.
MAKE SURE IN THAT E-MAIL YOU INCLUDE YOUR NAME, ADDRESS, AND PHONE NUMBER!!
Be prepared. The lab may ask for more images - THE LAB WILL LET YOU KNOW IF A SAMPLE NEEDS TO BE SENT - There is a $20-25 dollar fee (if they need a sample sent).
Lab email: <personal data hidden>
Lab phone:<personal data hidden>
Hours of operation: Monday through Friday, from 8:00 AM to 5:00 PM.
PLEASE READ BELOW ON PREPARING YOUR SAMPLE (if the lab needs a sample)
From the lab: Please do not ship samples on Fridays. They thank you for your patience and understanding.
Every sample must be accompanied by a completed submission form. Please place the form in a separate resealable bag to prevent it from getting damp or soiled. The form is at this link: https://www.canr.msu.edu/pestid/uploads/files/General_Sample_Submission_Form_May2022.pdf.
Complete details of submitting a sample are at this link: https://www.canr.msu.edu/pestid/submit-samples/
I hope this helps!
