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Lilac - blight, leaf miner, or…??? #873429
Asked June 17, 2024, 12:11 PM EDT
Hello. I am having an issue with four mature lilac bushes - all at least 40 years old. They have brown dead spots that through Google match the description of damage caused by leaf miner ants or lilac blight. No fully curled up leaves or caterpillars are present. I am trying to figure out what treatment options are available. Any advice would be much appreciated. I’m open to cutting them all the way back but don’t want to do anything drastic without being more certain of the cause.
Essex County New York
Expert Response
Thank you for reaching out with your inquiry!
I would suggest trimming back any diseased or affected branches, not a drastic cut back but enough to where the plant isn't dedicating any energy to the dying branches.
To better assess what is affecting your lilac bushes, I suggest sending a sample of it to the Cornell Plant Diagnostic Clinic.
I am attaching the link to the Cornell Plant Diagnostic Clinic. This link will provide all the pricing and the instructions you need to send out your sample to help ID what is affecting your lilacs. This is the best way to go about diagnosing your trees! The lab will send you back a full analysis as well as treatment recommendations. http://plantclinic.cornell.edu
And here is a link to the sample collection instructions: http://plantclinic.cornell.edu/collectandsubmit.html
