Michigan Technological University graduate student Anne Collins holds up a "capp stick," a tool used to measure the diameter of ash trees. After measurements are taken, pieces of bark are cut off an ash tree, rather than completely removing all of the bark off the tree. This "windowing" technique is performed to detect Emerald Ash Borers, while complete bark removal is used to learn the extent of the insect infestation in the tree. No insect infestations were found Tuesday, October 13, when researchers felled girdled ash trees in St. Ignace and stripped their bark in search of Emerald Ash Borers (EAB). The work is part of an ongoing series of EAB-related studies conducted by Michigan Technological University to ascertain the intensity of borer infestation in downtown St. Ignace, the effectiveness of new bait on purple traps, and the efficiency of bark removal techniques.

In the experiment, ash trees next to purple-trap-bearing ashes were girdled to attract the insect. Girdling stresses the tree, which attracts the bug. The traps were put up in June to test a new type of insect bait.

The girdled trees were cut down last week by consultant forester Bernie Huetter, while MTU graduate students Anne Collins and Jonathan Carlson and MTU laboratory technician Melissa Porter stripped the bark

Two techniques were used to remove the bark. The first was a "window" bark removal technique in which the diameter of parts of the tree was measured using a cap stick. Once the diameter is obtained, the bark was removed to a certain point depending on the measurement. The second technique used was complete bark removal.

The intention, Mr. Carlson said, is to determine a more efficient way of detecting EAB larva. Windowing is easier than stripping an entire tree, and can be used to detect if a tree has been infested by the borer. Completely removing the bark of a tree yields more data, including the number of larvae the tree has been infested with and their age. No matter what technique is used, shearing the bark is typically done in layers to avoid cutting into the galleries, the tunnels created by the burrowing insect. Small-size galleries indicate young larvae, while larger galleries are a sign of older larvae.

No ash borers were found in the girdled trees in downtown St. Ignace, Ms. Collins said. No borers were detected on the purple traps removed September 23, either. The results of the university studies will be prepared in December or January, Ms. Collins said.

The insect has now been detected in Alger County, with a single borer found on a purple trap, said Brenda Owen of the Slow Ash Mortality project Monday, October 19. Eleven beetles were also found in Chippewa County near Brimley, Mrs. Owen said. Officials from the Michigan Department of Agriculture are working with both counties to develop a plan to address the insects. A quarantine of both counties is under consideration, Mrs. Owen added. Alger was not quarantined in the past, while Brimley State Park was quarantined previously.

Studies in the Upper Peninsula are going well, she said. Girdling has inhibited EAB movement by presenting trees that seem to be more desirable to insects than moving to a different area in search of a host, Mrs. Owen said. A better understanding of the life cycle of the insect has also been determined, as researchers have found the beetle remains in its larval stage longer in the colder weather of the Upper Peninsula than in southern Michigan.