Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous Trees > Prunus > Sticky gums exuded from branches or twigs
Prunus > Branches > Sticky gums exuded from branches or twigs
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Branch cankers
Valsa leucostoma, Leucostoma spp.
- Sticky gum exudes from branch cankers
- Raised black pimple like fungal structures form on cankers and dead branches, exude orange tendrils of spores in wet weather
- Cankers are brown to black sunken areas on branch that may have cracked bark and discolored reddish brown sapwood
- Leaves on random branches wilt, turn yellow then brown
- Infected branches don't leaf out in spring
- Random dead branches seen throughout canopy
- Common on trees stressed by drought, winter injury, wounds, insect feeding or other factors
- More information on canker
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Brown rot
Monilinia fructicola
- Sunken, darkened areas on twigs from which gums are exuded, also known as gummosis
- Sudden browning of blossoms or wilting of leaves
- Part or all of the ripening fruit develop a soft brown rot, then become shriveled and dusted with powdery tufts of tan to gray spores
- Rotten fruit may remain attached to the tree or fall to the ground
- More information on Brown rot
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Bacterial spot and canker
Pseudomonas syringae pv. syringae
- Sticky gums (gummosis) or sour-smelling liquid are excreted from infected branches
- Blossoms turn brown, especially after frost damage
- Angular, brown to black leaf spots that eventually drop out leaving holes and giving a ragged appearance on leaves
- Sunken dark colored elliptical cankers form on branches
- More information on Bacterial spot and canker
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Mechanical damage
- Rubbery sap exudes from openings or wounds called gummosis
- Areas of bark are missing from stem or branches
- If bark removal encircles stem or branch, thinning canopy or branch dieback will be seen
- Leaves are undersized and yellow
