A couple of years ago, my neighbor asked me what all “the black stuff” was covering the exposed roots and area around the base of his large beech tree. I looked at it and thought, “Ah, that’s the same stuff I’ve seen on branches in the woods.” The next time I saw some, I cut off a branch and brought it home. Because I taught a high school ecology class at the time, I was particularly excited when I found out that it was a black sooty mold associated with the beech blight aphid. I found a great description on Tom Volk’s web site – his September 2007 Fungus of the Month, Scorias spongiosa.
This is the time of year for them. The beech blight aphid associated with the Scorias are cottony little buggers, and if you keep your head pointed down while hunting fungi, you might get a mouthful of “powder” from a low hanging branch – I have!!
Tom explains the process well, so read what he has to say. The picture below is the asexual stage of the fungus growing on the honeydew, or droppings, from the aphid. From the ground, you might say, “Wow, look! A coral mushroom growing in a tree”. Look closer. In a few days it will turn black as the mold begins to reproduce sexually.
Photo on the left is a close look at a beech blight aphid colony on a branch. Tom Volk’s site includes a video of the critters swaying and wiggling. That’s why this photo is out of focus – they’re dancing.