Understanding and Managing Gummosis on Stone Fruit Trees

Gummosis—excessive sap flow on peach, cherry, or plum trunks—is usually caused by bacterial or fungal canker entering through wounds or poor pruning cuts. The tree exudes gum to seal the infection. No spray cures it; the tree must fight it internally. Support tree health with annual lime (1 cup per inch of trunk diameter) to raise pH, proper watering, and good pruning practices.

Check gum for sawdust—if present, borers may be involved; contact Extension. Otherwise, focus on cultural care to help the tree compartmentalize the damage.