We have been seeing this in the park for the past couple months.  It just keeps getting bigger.  GROSS!!!

 

I put the Seek app on it and learned that it is Black Sooty Mold, Scoria spongiosa.  Now here's the interesting part, from Wikipedia:   Scorias spongiosa is a sooty mould fungus that grows on aphid honeydew.  It is found only on American beech trees, Fagus grandifolia.

 

Yep.  This is definitely American Beech.  And when we first noticed it there was a branch above this one, full of tiny white egg looking things.  Seek called them Beech Blight Aphids.  That was September 6th.  I didn't save the aphids picture, sorry, but the Wikipedia picture looked exactly like my Seek picture. 

 

Here's what Wikipedia said about Beech Blight Aphids:   Deposits of sooty mold caused by the fungus Scorias spongiosa build up below the colonies growing on the copious amounts of honeydew the insects exude.  The aphids do not usually cause much damage to overall tree health, but dieback is occasionally seen on very heavily infested branches. If infestations are heavy, twigs may die, but damage to the tree is usually minor. 

 

That's good news.  And fascinating information, if you ask me.  I love learning about this stuff.  Now when I see the aphids and the mold, I'll know that they are doing exactly what they were designed to do:  work together.  More good news.  ;D  

 

I guess it's not so gross after all.

 

 

HAPPY GARDENING!!!