Question
There are a number of lacebark elms where I go for walks (in Tallahassee, FL).  Just recently I have noticed clumps (usually circular or oval in shape) of tiny grey insects (with some black insects mixed in) that gather on the outside of the bark of the trees.  I can touch them lightly with a pine straw and the scatter . . . then come back together in a clump.  Very interesting.  What are these?

Answer
Hi Judee, I am surprised that you have seen something on the Ulmus parvafolia.  It may just be there and not causing a problem, as they are very disease resistant trees.  I have a few in my yard and love them.  Mine are the weeping variety of Chinese Elm.  There may be a new bug out there has not been noticed yet?   kathy