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mold or insect infestation? #879189

Asked July 29, 2024, 9:35 AM EDT

I discovered these while spots on my magnolia bush. When taken off and squeezed, an oily black substance emerges. Is it mold or insect? How do I (and should I) deal with this to keep my plant and yard healthy?

Dakota County Minnesota

Expert Response

Thank you for writing.
That is classic magnolia scale. It is killing magnolias all over MN.
https://northerngardener.org/magnolia-scale/
Measures to treat it are described but in truth, magnolia is not succeeding in MN these days.
https://mortonarb.org/plant-and-protect/tree-plant-care/plant-care-resources/magnolia-scale-neolecanium-cornuparvum/
Steve Miles, Master Gardener, Hennepin County MN (I am a human being, not a bot nor AI). I am an avid gardener but am not a degreed or certified horticulturist or arborist. I am happy to receive follow-up questions if my responses are incomplete or unclear.  This is the University of MN' garden soil testing service.  https://soiltest.cfans.umn.edu/testing-services/lawn-garden This is guidance on how to find a tree expert.  https://extension.umn.edu/planting-and-growing-guides/how-hire-tree-care-professional The Minnesota Landscape Arboretum is a wonderful place to see and learn about plants that grow in Minnesota. https://mngardens.horticulture.umn.edu/minnesota-landscape-arboretum Replied July 29, 2024, 1:40 PM EDT

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