Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous Trees > Prunus > Unusual growth on trunk or branches
Prunus > Trunk/Branches > Unusual growth on trunk or branches
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Black knot
Apiosporina morbosa
- Lumpy olive to black elongate swellings along all sizes of twigs
and branches - Gall formation may cause leaves to wilt or not leaf out showing branch dieback
- Rough black cracked swelling can occur on the main trunk
- Most common on choke and pin cherry
- More information on Black knot
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Crown Gall
Agrobacterium tumefaciens
- Galls, a large rough woody growth, form on roots or at the base of the trunk
- Galls are light colored when young, and turn dark brown to black, rough and cracked with age
- Growth of young plants with several galls is stunted
- Infected plants more susceptible to drought stresses or winter injuries
- More information on Crown Gall
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Mechanical damage
- 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
- Rubbery sap exudes from openings or wounds called gummosis
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Scurfy scale
Chionaspis furfura
- Infested twigs and branches show dieback in canopy
- Adults are white and covered by a white cocoon-like armor, which gives the appearance of white bumps along the stem or branches
- Crawlers or juvenile scales are light purple
- Cocoon-like armor can be seen year round but crawlers can be seen in June
- More information on scale insects
