Beware the tree-eating beetle

Beware the tree-eating beetle

Two weeks ago, we printed a photo of a purple box hanging from a tree at the Hannah Dustin Memorial park and ride in Boscawen. In addition to posing our own theory of a cleverly executed alien invasion, we asked you, readers, for thoughts on what the box might be.

Several of you searched the web and discovered that the box is actually a trap for insects. While this is less fun than aliens, we have to concede that this is correct, especially after speaking with Douglas Cygan, invasive species coordinator for the state Department of Agriculture. He writes:

Yes, the purple box hanging from a tree at the park and ride in Boscawen at the Hannah Dustin Memorial is a sticky trap for monitoring the presence of Emerald Ash Borer (EAB, Agrilus planipennis). This one in particular is one of mine. This year alone, 110 traps have been placed throughout New Hampshire by the Department of Agriculture, Markets and Food, Plant Industry Division. This is our division's second year participating in a nationwide survey being administrated by the USDA Animal and Plant Health Inspection Service. In 2008, our division set out 150 traps.

The trap's purple color is no accident - research found that this is the most effective color for attracting the EAB. The attraction is further enhanced by the addition of highly aromatic manuka oil, which is derived from a plant and is chemically similar to the natural volatiles given off by ash bark and wood. The traps are hung about 20 feet off the ground, preferably in a living ash tree. There's no need to be concerned about the potential for these traps luring EAB from other infested areas since they will only attract beetles that are within close proximity. Currently there are no known occurrences of EAB here in New Hampshire.

Is there anything better than having someone else do the work for you? Not really. But we did do a little digging of our own to appear less lazy.

According to the national emerald ash borer website, operated by a grant from the U.S. Forest Service, EAB was discovered in the states in southeastern Michigan in 2002. It is believed that the beetle arrived here on solid wood packing material originating from its native Asia. EAB can now also be found in parts of Ohio, Indiana, Illinois, Maryland, Pennsylvania, West Virginia, Wisconsin, Missouri, Virginia and most recently, Minnesota and New York.

The adult beetle feeds on the leaves of ash trees and causes minimal damage. It's the larvae that cause the most problems - call them the unruly teens of the bug world. They feed on the inner bark of ash trees, disrupting the trees' ability to transport water and nutrients.

Since its arrival in the U.S., the beetle has killed tens of millions of ash trees, though the species has not been detected here in New Hampshire. They'll have to get through Vermont first, which is something of a comfort.

If you'd like more information on EAB or are interested in looking at some gross bug photos, visit emeraldashborer.info. In the meantime, enjoy the colorful addition to New Hampshire's treescape.