Joel Bird, Blandford Volunteer, inspecting the trees for beech bark scale
August is national Tree Check Month, which makes it a great time for Michiganders and travelers alike to be on the lookout for invasive, destructive pests threatening the state’s forest landscape. The Michigan departments of Agriculture and Rural Development, Environmental Quality and Natural Resources, along with the U.S Department of Agriculture, are asking people to take time out this month to examine trees for signs of Asian longhorned beetle, a highly destructive invasive pest.
Take just 10 minutes this month to check trees around homes for Asian longhorned beetle or any signs of the damage it causes. Out for a stroll? Look for signs around the neighborhood, at local parks and favorite recreation spots. Early detection and response are vital to protecting Michigan’s trees.
Adult Asian longhorned beetles are distinctively large, ranging from three-quarters of an inch to 1 and one-half inches in length, not including their long antennae. The beetles are shiny black, with random white blotches or spots, and their antennae have alternating black and white segments. They have six legs that can be black or partly blue, with blue coloration sometimes extending to their feet.
The Asian longhorned beetle was first identified in the United States in 1996, likely transported from Asia in wood packing materials. Like the emerald ash borer, the Asian longhorned beetle spends most of its life cycle eating its way through the insides of trees. What makes ALB much more dangerous is that it feeds on a wide variety of tree species. Its first choice is maple, but it also will infest birch, elm, willow, buckeye, horse chestnut and other hardwoods. The damage caused by Asian longhorned beetles ultimately will destroy an infested tree.
Adult beetles are active in late summer to early fall. During that brief window, beetles may be seen and some of the telltale signs of infestation may be more noticeable. Female beetles chew oval depressions in which they lay eggs. When larvae hatch, they burrow deep into the heartwood of the tree where insecticides can’t reach, creating large chambers in the wood. The next summer, fully formed adult beetles emerge from trees by boring perfectly round, three-eighths-inch-diameter exit holes. Sometimes a material resembling wood shavings can be seen at or below these holes or coming from cracks in an infested tree’s bark. Once a tree is infested, it must be removed.
To date, there are no known infestations of Asian longhorned beetle in Michigan. However, the beetle has been found in areas of Ohio, Massachusetts, New York, New Jersey, Illinois and Ontario (Toronto).
“Though the beetle does not move long distances on its own, it can be transported in firewood,” said John Bedford, Pest Response Program specialist at the Michigan Department of Agriculture and Rural Development. “When traveling, leave your firewood at home. Buy it at your destination point and burn it there.”
Anyone observing an actual beetle or a tree that appears to be damaged is asked to report it. If possible, capture the beetle in a jar, take photos, record the location, and report it as soon as possible through the USDA’s Asian longhorned beetle website, www.asianlonghornedbeetle.com or contact MDARD at 800-292-3939 or MDAemail@example.com.
MDARD’s Asian longhorned beetle Web page provides more information and photos to help identify the beetles and signs of the damage they cause to trees.