Update on lilac mold preventative treatments? - Ask Extension
Hello!
I've read your advice on the lilac problem, but it isn't working on my group of old lilacs. Could you please add an article with updates on ho...
Knowledgebase
Update on lilac mold preventative treatments? #929439
Asked April 23, 2026, 11:34 PM EDT
Hello!
I've read your advice on the lilac problem, but it isn't working on my group of old lilacs. Could you please add an article with updates on how to care for lilacs during this new mold era? For two years in a row, my old lilacs have gotten white spots in mid summer, then brown and drop, and then in fall they start to produce buds and bloom again. I did clear out the leaves underneath the second year, but it still happened in year two. I'd like to get ahead of it this year. In addition to clearing out old leaves and pruning, should I spray a fungicide? If so, how often and when to start? Will fungicide be toxic to the birds? The lilacs do look healthy in spring and early summer and then the wilt happens.
Thank you!
Ramsey County Minnesota
Expert Response
Our advice has not changed although I am giving you a link to our most recent article. You can use fungicides as long as they are applied prior to the onset. They will not poison the birds or insects. Thanks for the question. I reminded me that I need to do that also. I had the problem for the first time last year on a hybrid lilac that had previously not been affected.
