Loudoun had some heavy winds early this winter.  

Cankers on maple tree twigs can be characterized by: 

• Discolored / sunken areas: Cankers usually appear as sunken, discolored lesions on the twigs or branches. These areas may be dark brown, black, or gray, often contrasting with the surrounding healthy bark.  This is much easier to diagnosis during the growing season.  
• Cracked or broken bark: The bark around the canker may crack or peel away, exposing the underlying wood or forming crevices.
• Oozing sap: Cankers release sticky sap in the affected area. 
• Dieback: Branches affected by cankers can cause leaves to wilt, yellow, fall prematurely. Twigs can dieback
• Fungus: Small fungal fruiting bodies can appear in the affected area. 

Another considerating is the ground twigs were damage from previous years of cicada egg laying. Female cicadas use an appendage, called an ovipositor, to gouge longitudinal slits in twigs into which they then deposit eggs.  Cicadas field research has found they have a preference for trees with smooth branches about 3/16" to 7/16" in diameter in which to lay their eggs. Maples are often listed in the top of lists for preferred trees. Mature trees will have some damage at the branch tips, but this is not considered a significant risk, as it is a natural form of pruning that a tree can sustain.  Smaller and newly planted trees have more risk of damage.  

Cankers can weaken the overall structure of the tree, making it more susceptible to environmental stressors. Small tender twigs at the end of branches will be be more impacted by the drought, which Loudoun has been more regularly seeing.  The multiyear effect of drought cycles can weaken trees which attracts more disease and insects.  

I am unable to provide a definitive diagnosis, particularly at this time of year. Next summer, if you are seeing more branch flagging, pre-mature leaf drop, or evidence of heavy Spotted Lanternfly feeding (Silver maples are a favorite) please email the MG Help Desk photos or consider contacting a certified arborist to support an on-site inspection for any high value specimen trees in your landscape. 

-Becky

Becky,