Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous Trees > Maple > Growths or bumps on branches or trunk
Maple > Trunk/Branches > Growths or bumps on branches or trunk
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Cottony maple scale
Pulvinaria innumerabilis
- Nymphs are brown-translucent, 1/5 inch; females lay eggs in the white marshmallow egg-sac along the twigs and small branches
- Young insects remove sap from leaves creating a speckled appearance and possibly yellowing leaves in mid to late summer
- Excrete honeydew, a sticky, shiny material, on leaves and branches; sooty mold may also result from honeydew
- Heavy infestations cause premature leaf drop and branch dieback
- Silver maple is preferred host
- More information on Cottony maple scale
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Phomopsis galls
- Galls are round woody balls, occurring individually or clustered on twigs or branches
- Range in size from 1/4 to 2 inches in diameter
- More information on Phomopsis galls
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Oystershell scale
Lepidosaphes ulmi
- Heavy infestations of “shells” can completely cover bark
- Feeding can cause foliage to yellow
- Twig and branch dieback can occur when branches are heavily infested
- Light to dark brown, elongated, 1/10 to 1/8 inch long, found feeding on branches
- Damage occurs during summer
- More information on Oystershell Scale
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Burls
- Large round to semi-circular swellings along main trunk or large branches
- Many buds or sprouts may be present on the exterior of the burl
- Common on sugar and Norway maples
- Burls continue to grow as the tree grows
- While burls do not kill trees directly they can reduce a tree's health and lifespan
- There is no known cause for burls
- More information on Burls
