Emerald ash borer found in Menominee County

Invasive insect previously sighted in neighboring counties
By: 
Luke Reimer
Reporter

The Menominee Indian Tribe of Wisconsin was recently made aware of an emerald ash borer infestation near Legend Lake in Menominee County.

Emerald ash borer is a beetle, native to China, that feeds on ash trees starting at the top of the tree and working its way down.

“The tribe does insect trapping and we specifically put those traps near large ash trees,” said Ben Degner, the tribe’s environmental project coordinator. “We had what we thought were seven adult emerald ash borers about a month ago. A Menominee County forest representative was driving through the reservation one day and he said that he saw a decrepit ash tree. That happened around the same time we found our sample.”

Degner added that, when the tree was examined, many woodpecker holes were apparent. He said this is due to woodpecker feeding on the larvae of emerald ash borer.

“They will just trash a tree when they find out that the emerald ash borer is there,” said Degner. “When we saw that, we kind of knew what was up.”

He added that a DNR representative started to strip the bark off of the tree and that is when Degner said that he saw many different emerald ash borer trails through the tree.

“We also found a live adult in there,” said Degner. “We sent that bark to get it tested in Pennsylvania and it came back positive.”

Degner said that emerald ash borer is still new to Wisconsin and the United States, since it was only discovered in the country roughly 20 years ago, making it hard to find a defense to it.

“It essentially just destroys ash trees in a couple of years,” said Degner. “There are hundreds and hundreds of bugs that can get into an ash tree. They just eat the tree alive until it dies.”

Due to it taking about three years to notice if the insects have plagued a tree, Degner said that it is very hard to prevent the insects.

“The DNR rep said that that the tree that we saw was probably four years old,” said Degner. “There was two other trees nearby that were starting to become affected as well.”

In regards to how the insects got to Menominee County, Degner said that the main way that emerald ash borer travels is through firewood transfer.

“At this particular piece of land, there was firewood and a lot of it was pretty clearly ash wood,” said Degner. “This could especially happen if you buy firewood at a small stand by your house and bring it to your vacation home.”

According to Degner, this instance was the first time that emerald ash borer had been detected in Menominee County. Emerald ash borer was also spotted in Oconto and Shawano counties in 2020 and in Shawano city trees in 2021.

“Everybody knew it was coming, because it has slowly been surrounding us,” said Degner. “The tribe’s forestry department has been active in searching for it.”

In terms of defense for the emerald ash borer, Degner said that insecticide can be used, but can be costly. He added another method that can combat the pests is to use three different varieties of wasps that kill larvae and adults.

“The DNR has started to implement that and it has had a pretty good success in the state,” said Degner, “but we can’t do it until there is an established population of emerald ash borer, otherwise the wasps will just die off. Right now, does the reservation have a high enough population for that? We don’t know.”

In terms of preventing the pests from appearing, Degner said that there is not much that can be done outside of firewood transfer bans.

“Emerald ash borer does not travel very fast by itself naturally,” said Degner. “The main prevention was always outreach, but it only takes one or two people to not adhere to that.”

Degner added that these insects do not have any direct harm to humans.

“The main thing is that it is a financial burden, because you have to remove those trees,” said Degner.