Unusual foam on autumn fallen leaves does not belong to a spittlebug, but may be a type of fungus.
Observation by Stephen Payton:
Noticed this foam/bubbles on a leaf while out hunting. Can't recall seeing this before. After some online searching, it looks like it could be "spittlebug" foam.
Derek Sikes, Entomologist with the University of Alaska Fairbanks (UAF) Museum of the North, writes:
I don't know what those bubbles are from but spittle bug nymphs only feed & make their spittle on living green plants - not on fallen leaves. They tap into the xylem system (that's under pressure) and feed on it and make their bubbles from it.
I suppose it's possible it was made before the leaf fell... (but I can't recall any spittlebugs feeding on trees or shrubs, just on grasses and forbs). The easiest way to know is to search in the spittle for the nymph. If there's nothing there, then it's not a spittle bug.
So.. I doubt that's made by a spittle bug. Even if it were made by a spittle bug, there'd be no way to identify the spittlebug to genus without a good photo of the specimen, preferably the adult (with wings, which doesn't make spittle - only the nymphs do).
Steve Trudell with the Puget Sound Mycological Society writes:
It's hard to tell from the photos - it might be the mycelium (vegetative body) of a fungus but I can't be sure. If you have a higher resolution file that might make it easier to see detail and possibly figure out if it's a fungus or not.
Comments from LEO Editors:
This observation has been forwarded to the UAF Cooperative Extension.