Knowledgebase

Aster disaster ? #940447

Asked July 24, 2026, 5:03 PM EDT

My Asters-2nd year, are dying from the ground up. None of the nearby perennials seem to be affected. They do get water regularly but I haven’t fertilized this year yet. There is a yellow powdery substance on the dying leaves. Can you help me identify the cause/treatment.

Kent County Michigan

Expert Response

Your asters are infected with Aster Yellows. Aster Yellows is a bacterial disease that is caused by phytoplasma and is incurable. Aster Leafhoppers move the phytoplasma from plant to plant. The infected plants should be removed from your garden and destroyed. Also check around for weeds that have similar symptoms and destroy them. Mow any tall grass nearby to reduce aster leafhopper habitat.


This article from the University of Minnesota Extension contains more information. Aster yellows | UMN Extension The University of Wisconsin Extension also has an article on aster yellows, Aster Yellows – Wisconsin Horticulture .


Thank you for your question and have a great gardening season.


Thank you for your question! and have a great gardening season. Replied July 26, 2026, 1:13 PM EDT

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