Continue to watch for emerald ash borer. Recently, new infestations were reported in the Lansing, Michigan, area and in Ohio across the state line from Fort Wayne, Indiana. These infestations are considerably closer us than those previously reported in the Detroit, Michigan, and Toledo, Ohio, areas.
Movement of this pest from infested areas is most likely on firewood and nursery stock. This pest was detected and identified in North America in July 2002, but estimates are that it has been in southeastern Michigan for 8 to 10 years. Ashes moved out as nursery stock during that time could easily have been infested. This beetle is common in younger as well as older trees. If you obtained nursery stock from that area during the last 10 years, scout areas where it was planted for signs of this beetle.
Infestations have been found in Michigan in green, white, and black ash. It would likely attack blue ash as well, but that plant is not common in southeastern Michigan. In Asia, it attacks Ulmus davidiana var. Japonica, used in some crosses for American elm replacement varieties. Look for 1/8-inch, D-shaped holes in the bark—similar to exit holes of bronze birch borer. Infested ash trees first show dieback of upper branches, progressing to death of major branches, water sprouts on the trunk, and finally, water sprouts at the base of the otherwise dead tree. If suspects are found, contact the Illinois Department of Agriculture, your local U of I Extension office, or me.