Those purple boxes hanging in trees

A couple years ago while driving in Pennsylvania (around the Erie area, I think we were on our way to Ohio) we started noticing some weird purple plastic three-dimensional triangle-shaped boxes hanging in trees. We had no idea what they were, but we steadily started seeing more and more of them. This spring I noticed that one had been put up on my way to work, and I think there are some along the thruway headed toward Buffalo, but I still didn't know what they were. I figured they were some type of environmental project and asked a few of my sciencey friends if they knew what the boxes were...but they didn't.

So in the conservation building at the fair this year I saw a little leaflet that described what they are! So now I know! And because I want to put this paper in the recycling bin so it's not cluttering up our house, but I don't want to lose the info, I'm posting it on my blog. I'd like to find a picture of one of the boxes but I'll probably just have to stop and take one myself. Here are the facts listed on the card:

Q: What's purple, sticky, and hangs in an ash tree?
A: It's a detection tool that's being used in your state and 46 other states across the country to survey for the emerald ash borer (EAB) beetle. For convenience, we call these detection tools "purple traps."

Q: Who is conducting the EAB survey?
A: The US Dept of Agriculture's Animal & Planet Health Inspection Service (APHIS) and State Depts of Agriculture or Natural Resources are cooperating partners in the survey effort.

Q: How do the purple traps work?
A: During EAB adult flight season, beetles fly around ash trees, nibbling on leaves & looking for a mate. If an EAB lands on the purple trap it will get stuck in the glue.

Q: Is the purple trap safe?
A: The purple traps pose no risk to humans, pets, or wildlife, however the non-toxic glue can be extremely sticky & messy if touched.

So now we know that the purple boxes are traps for the Emerald Ash Borer Beetles. I know they're "only bugs," but it seems a little inhumane to trap the bugs (and other flying creatures, like bats and birds?) in that manner.

http://www.aphis.usda.gov/plant_health/plant_pest_info/emerald_ash_b/index.shtml