Lilac Disease - Ask Extension
Client has sick lilac tree.
Knowledgebase
Lilac Disease #847597
Asked August 28, 2023, 11:34 AM EDT
Client has sick lilac tree.
Chippewa County Michigan
Expert Response
Hello,
Based on what I see in your images:
Brown spots on lilac tree leaves can be caused by several fungal pathogens. Leaf spot disease is one of them and can cause the leaves to turn yellow and then brown and die back. Another possible cause of leaf discoloration is powdery mildew’s fungal disease. Lilac leaves may also turn brown if they are damaged by frost or cold weather. Lilac leaves may turn brown if exposed to too much sun. Lilac leaves may also turn brown if insects are attacking them. This looks like Lilac Pseudocercospora Leaf Spot.
References:
Summer Foliar Lilac Diseases - Iowa State University - At this link: https://hortnews.extension.iastate.edu/2021/08/summer-foliar-lilac-diseases
Lilac Pseudocercospora Leaf Spot - Iowa State University - At this link: https://hortnews.extension.iastate.edu/lilac-pseudocercospora-leaf-spot
Signs and symptoms of plant disease: Is it fungal, viral, or bacterial? - Michigan State University - At this link:
https://www.canr.msu.edu/news/signs_and_symptoms_of_plant_disease_is_it_fungal_viral_or_bacterial
Lilac Bacterial Blight: Pseudomonas syringae pv. Syringae - Cornell University - At this link: http://plantclinic.cornell.edu/factsheets/lilacbacterialblight.pdf
You should get a confirmed diagnosis from the MSU Diagnostic Plant & Pest Lab - Please email your digital images 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-sample.
I hope this helps!
Based on what I see in your images:
Brown spots on lilac tree leaves can be caused by several fungal pathogens. Leaf spot disease is one of them and can cause the leaves to turn yellow and then brown and die back. Another possible cause of leaf discoloration is powdery mildew’s fungal disease. Lilac leaves may also turn brown if they are damaged by frost or cold weather. Lilac leaves may turn brown if exposed to too much sun. Lilac leaves may also turn brown if insects are attacking them. This looks like Lilac Pseudocercospora Leaf Spot.
References:
Summer Foliar Lilac Diseases - Iowa State University - At this link: https://hortnews.extension.iastate.edu/2021/08/summer-foliar-lilac-diseases
Lilac Pseudocercospora Leaf Spot - Iowa State University - At this link: https://hortnews.extension.iastate.edu/lilac-pseudocercospora-leaf-spot
Signs and symptoms of plant disease: Is it fungal, viral, or bacterial? - Michigan State University - At this link:
https://www.canr.msu.edu/news/signs_and_symptoms_of_plant_disease_is_it_fungal_viral_or_bacterial
Lilac Bacterial Blight: Pseudomonas syringae pv. Syringae - Cornell University - At this link: http://plantclinic.cornell.edu/factsheets/lilacbacterialblight.pdf
You should get a confirmed diagnosis from the MSU Diagnostic Plant & Pest Lab - Please email your digital images 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-sample.
I hope this helps!
