Dwarf Stanley Plum oozing sap

Asked November 8, 2016, 9:57 AM EST

The Dwarf Stanley Plum is about 12' tall and was purchased and planted 2-3 years ago. In 2015 it produced fruit. In 2016 there was a cold spell while it was in bloom. Recently, near the bases of the lower branches there are blobs of sap. I'm assuming some bore has attacked. I've not removed the blobs of sap to investigate. Should I? What am I dealing with and what are the treatment options? Would the bore hole be straight or bent? What is the life-cycle and size of the pest at this time of year? Soil is typical Damascus clay and rock with good sloping drainage.

Montgomery County Maryland fruit stanley plum oozing sap

1 Response

Gummosis, or oozing of sap can be caused by injury, stress, or boring insects.
Is the sap clear or did it have frass/sawdust in it? Clear suggests injury or stress, while frass, which is a combination of sawdust and fecal matter, suggests borers.
Here is our publication on the problems on stone ( pitted) fruits:
https://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG77_IPM_Series_Sto...
Growing tree fruits is challenging in our areas without a lot of careful management including a well-timed spray program for pests and disease.
Here is home fruit orchard guidance from Virginia Tech for your reference:
https://pubs.ext.vt.edu/456/456-018/Section03-Home-Fruit-Disease-and-Insects.pdf

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