spittling spittles bugs
Based on comments on your site, I think this may be the work of spittle bugs of some sort…is that one of the bugs to the left of the spittle bubbles? Taken in Bowling Green, OH
You are correct. This is the foamy spittle from a Spittlebug. The spittle is secreted by the Spittlebug’s anus and it serves as a protective environment so the nymph can safely feed on plant sap. Adults are winged and look like Leafhoppers. They are sometimes called Froghoppers. BugGuide has additional information. The insect visible in your photograph is an Aphid.