Tree's have a disease and are being cut down...are sprayed in spring but are still dying

Asked September 12, 2017, 2:40 PM EDT

Live in a townhouse at The Gables at the Reserve in Plymouth...we have blooming crab apple trees (?) planted over the complex... the tree 1/2 dead is representative of what is dying...the association has cut down about 20 of these trees' and does spray in the spring. Must be spraying for the wrong disease since they keep dying...can you determine what disease it has and what is should be sprayed with? Will send another email with same type of tree with black on trunk. Thanks for any help you can give.

Hennepin County Minnesota crabapple disease cankers on crabapple

1 Response

We can't identify what's killing the trees with any certainty by viewing the photos. However, based on your description and what we can see in the photos (black stains on the trunk), it's possible that the trees have been damaged by a fungal pathogen called black rot Botryosphaeria obtusa. Go here to learn about this disease:
https://www.extension.umn.edu/garden/yard-garden/trees-shrubs/black-rot-canker/

If the folks who care for the trees want to save any that are still healthy, they should ask a certified aborist to assess the trees' health onsite and recommend a course of action.

Sometimes laboratory analysis is needed to properly identify plant diseases. If that's necessary, take or send sample of parts that show evidence of disease to the University of Minnesota Plant Disease Clinic.
https://pdc.umn.edu/submit-sample