Purple Confusion

So I've been having this conversation with myself over and over lately and could not figure out an answer. As I drive up the road each day I keep seeing this purple "bag" hanging in a tree. I have tried and tried to figure out exactly what it is doing there. I have went over many options in my head but not a one of them seemed to fit. Although I watch the news daily (too much, Dear One and the kids say) I never watch the local news but for some reason I left it on while I was doing things tonight and when I looked up there was my purple bag. So I cranked up the volume and couldn't believe my ears. It's a bug trap! Apparently we, and by we I mean my whole state, are having problems with the Emerald Ash Borer and this is the way for them to keep track of them. So now my mystery is solved and I can drive up the road without feeling I am going crazy because I'm talking to myself.

Picture of a trap like the one in the tree I pass daily, I would take a picture of the actual one but its in a bad curve and I'm not quite that crazy.