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First summer in new home, finding black slime/goo on apple tree #651716

Asked June 16, 2020, 12:49 PM EDT

Hello, Our new home has an apple tree in the back yard. We're learning how to maintain it. I've noticed "black goo" on some leaves/apples in isolated spots - pictures attached. Google says Black Knot possibly, but this looks and feels very viscous. Any ideas? Thanks!

Carver County Minnesota

Expert Response

Hello.

It sort of looks like a wetwood or slime flux but that amount on a small twig doesn't look right. I'd expect that on the trunk of the tree or on a large branch. I recommend having a certified arborist evaluate your tree or sending a sample to the U of MN Extension Plant Disease Clinic for a definitive diagnosis.

Here is a link to the U of MN Extension PDC where you'll learn about their services, prices, and how to submit a sample: https://pdc.umn.edu/

Here, also, is a link to information on how to find and hire a professional should you decide to go that route:

https://extension.umn.edu/planting-and-growing-guides/how-hire-tree-care-professional

I hope this information helps.
eGardener Replied June 20, 2020, 2:45 PM EDT

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