Massive gummosis at base of cherry tree

Asked July 25, 2020, 12:18 PM EDT

About 4 weeks ago, i noticed amber resinleading from a bulge at the base of my otherwise very healthy-looking sour cherry tree (Montmorency). I scraped it away looking for damage or bug signs, and found nothing. It has continued to ooze resin, and now it's coming from all around the base, and one spot about 3 feet up the trunk and far away from this mass. Does this look like fungus, bacteria, or something else? I hate to take thectree out, because it otherwise is very healthy-looking.

Montgomery County Maryland

1 Response

Cherry trees respond to bark injury, whether damage from something like a string trimmer or an insect by producing a sap flow called gummosis. In this way it hopes to push out an invader.
We think that your tree is suffering from attack by the Peach tree borer, which is a type of Clear wing borer (a wasp-like insect as opposed to boring beetles).
Here is our page that includes it:
https://extension.umd.edu/hgic/topics/stone-fruit-insects

It's impossible to say for sure how your tree will fare. Keep monitoring it and water in times of drought. It can be damaging, especially for young trees.


Christine