Michigan’s Invasive Species Program is encouraging residents to look out for signs of the invasive Asian longhorned beetle (ALB).
The Michigan Department of Natural Resources said there are currently no viable chemical controls, diseases or predators to help control the population. So the DNR says it's critical to identify signs of the beetle before it spreads.
The ALB is a wood-boring beetle that is considered invasive to North America. The species attacks at least 12 types of hardwood trees, including maples, horse chestnut, birches, elms and willows.
Cheryl Nelson is a Forest Health Outreach Forester for the Michigan DNR. She said August is the most common time to see signs of the ALB.
“This time of year, especially August, is a great time to check for ALB, because August is generally the time that the adult beetles emerge from the trees,” said Nelson. “Also this time of year, as well as other times of year, you can also see the damage that they cause from either the females chewing little depressions in the wood where they lay their eggs as well as the exit holes.”
The exit holes are approximately the diameter of a pencil. These holes can typically be found in tree trunks and branches.
“What happens is the beetles themselves, once that female lays the little egg in the little depression, then the little larvae, once it hatches, tunnel into the tree and they end up going in the tree so deep and so far that not only do conventional pesticides, insecticides not reach all of the tree, but also all of that damage and removal of that wood weakens the tree itself,” said Nelson.
Nelson said this becomes especially concerning in storms. She said if the tree has internal damage from the beetle, it will not recover and is more likely to fall.
But she said the beetles do not typically spread from one location to another rapidly.
Nelson said the beetles are known to jump from tree to tree rather than flying excessive distances. She said that is why the most effective control method is to eliminate not only the infested tree, but the surrounding trees as well.
“What happens is in an area where ALB is found, the only way to remove them, because chemical controls are not viable, is to remove all of that infested wood, as well as surrounding a buffer of trees around to help protect,” said Nelson. “That goes with them not being very efficient flyers or movers. So they do not move from tree to tree very fast or over land distances very fast. That keeps them in a more tight circle, a more controlled setting, rather than just spreading out very quickly.”
Another containment strategy the DNR is recommending is to not move firewood. Nelson said since ALB does not travel far on its own, moving firewood from one location to another may transport the beetle to new locations.
“Don't transport it from one household to another, one area of the state to another. Try and buy certified heat treated firewood at your location or look for certified heat treated firewood where possible. This is going to be the number one thing you can do to help prevent the spread of ALB, as well as other numerous invasive species in helping protect Michigan's urban and forested landscapes,” said Nelson.
