Last year I drove past one of these purple contraptions on my way to work, staring directly at it as I stopped at an intersection in rural Illinois. The color less than subtle, the box often caught my attention as I waited for a tractor to lumber past. Was it a funky purple birdhouse? A long-lost but incredibly sturdy kite? Some wayward science experiment that no one ever took down? I fancy myself a storyteller and could easily fashion a hundred reasons for that proud tree to flaunt such an eccentric bauble.
Recently I changed my driving route and noticed another box eyeing me as I edged past its home in a wooded area just off the highway. Curiosity tempted me to take a peek and I discovered that these are actually traps hung by the Illinois Department of Agriculture to determine the spread of the emerald ash borer
(EAB), an invasive beetle first detected in Illinois in 2006.
The EAB is native to Asia and was first spotted in North America in 2002, likely arriving via packing crates on cargo ships. Since then the metallic green insect has spread to 11 states and parts of Canada, threatening to destroy billions of ash trees by attacking the tissue that spreads nutrients and water through the tree. Larval populations leave infested tissue looking like a doodle board of serpentine swirls, with the adult exiting the tree through a D-shaped hole. Invaded trees experience a thinning canopy, often losing half their branches the first year of infestation.
The purple boxes get hung in May and are usually removed in August, after the beetle's flight season has ended. The traps themselves do not indicate a local problem, but are fitted with a sticky coating and lure to catch the beetles if any are lurking and help determine the extent of their spread across the state.
While the EAB has proven very difficult to kill, the bug is a slow mover and many measures are being taken to keep them isolated. One of the best strategies is not moving ash wood from a quarantined area, including nursery trees, logs and firewood. The beetles are notorious hitchhikers and are always eager to join you on a weekend getaway. During the summer camping season it is imperative to know where your firewood originated and to inspect it for any indication of the insect. Buy locally and don't take any leftover wood home with you.
My discovery of EAB traps came just in time. Emerald Ash Borer Awareness Week
begins May 23, 2010, with 16 states participating. A national effort will be made to educate the public about the spread of the beetle and its potential devastation to the entire ash population of North America, including the Buy it Where You Burn it campaign