DNR Releasing Wasps In Battle Against Emerald Ash Borer

The Oak Creek Common Council narrowly voted to allow the DNR to release stingless wasps, with some aldermen worried about introducing another non-native species to the area.

Oak Creek is trying a new way to battle the tree-killing emerald ash borer.

The Common Council has approved a proposal for the state Department of Natural Resources to release stingless wasps, which have been deployed elsewhere in Wisconsin and Illinois, in Oak Creek.

The wasps are less than a quarter-inch long and do not sting people or animals. City Forester Rebecca Lane said people will not notice they are present.

What they will do is slow down the spread of the emerald ash borer in Oak Creek, Lane said. The wasps kill the beetle at about a 60 percent rate.

However, some Oak Creek aldermen were leery about introducing a new species to the area. The council narrowly approved the wasp release by a 3-2 vote, with Aldermen Tom Michalski and Ken Gehl in opposition.

"We already have unintended consequences with other plants and animals being introduced into areas where they weren't native," Michalski said. "I'd just hate to come across a problem 10 years down the line that we didn't foresee."

After their introduction in northern Illinois and Newburg, Wis., it's likely the wasps would eventually make their way to Oak Creek either way, Lane said in a memo to council members. Allowing the DNR to release them now might save ash trees, she said.

Alderman Dan Bukiewicz said with the wasps probably coming to the area anyway, it made sense to do something now to try slowing down the EAB.

The release of the wasps comes at no cost to the city. The insects are provided by the U.S. Department of Agriculture, while DNR staff do the field work. It may save Oak Creek money in the long run by reducing the number of trees that need to be removed or treated, according to a report to council members.

The council delayed voting in January so it could get more information from the Oak Creek Health Department, which reported to aldermen earlier this month that the wasps do not have any known negative impacts on humans.

The initial release will likely be on the Milwaukee County-owned Oak Creek Parkway, Lane said.

The emerald ash borer was first discovered in Oak Creek in November of 2009. The beetle is a highly-invasive, destructive insect that feeds on the sap of ash trees, which are common in Oak Creek and throughout Wisconsin. Once an ash tree is infested with ash borer larva, it can die within a year.

The city has an estimated seven-year plan to remove and replace all ash trees in the city. Treatments to minimize the beetle's impact have taken place for the past three-and-a-half years.

The DNR first announced plans to release wasps to battle the EAB in May 2011.

me March 13, 2013 at 07:15 AM
Did the city take into account that God just might hate ash trees?
Mark Schaaf March 13, 2013 at 01:48 PM
it didn't come up, but seems plausible.
Martha Conover March 13, 2013 at 01:49 PM
What else do these feed on? Will they prey on beneficial insects as well? Introduction of non native species is scary.
Marty March 13, 2013 at 01:52 PM
I think Oak Creek needs dogs that shoot bees out of their mouths. Or sharks with laser beams on their heads.
Mark B March 13, 2013 at 02:03 PM
The term "unintended consequences" keeps popping into my head.
Joe B March 13, 2013 at 02:12 PM
Please let them eat Mosquitos also and I would raise them myself
Resident of O.C. Paul March 13, 2013 at 03:19 PM
The Emerald Ash Borer is native to Asia, and the Ash trees in Asia have built a resistance to them. The problem with the Ash trees here in the U.S. is that the Emerald Ash Borer is not native, and the Ash trees have no resistance or tolerance to them; so when the Emerald Ash Borer infests an Ash tree, it typically kills the tree. Only one thing can prevent this and that is genetically modifying, the Ash trees to be tolerant, or breeding ash trees that are tolerant of the borer which can take a lot of time.
Terri March 13, 2013 at 05:29 PM
The minute the white man stepped into this country. (And yes, I am white.) everything started to go downhill. White people were obviously a non-native species, and look what's happened. Now we are all back peddling to stave off the negative consequences of everything. No matter what OC does it's going to impact some part of the eco system. Grin and bear it guys!
me March 14, 2013 at 02:26 AM
So how should OC get ride of the white people to save the trees? I'm thinking if they did that the tax base for the city would be in the red. Hmm interesting problem we have here.
Bernie Blake March 14, 2013 at 02:47 AM
DNR hmmmmm. Just like the coyotes they planted here in the 90's. Great and then they will plant more cougars(not hot 40 year old women) into the state too!
Robin Usborne March 14, 2013 at 06:17 PM
Although it doesn't say in the article, this stingless wasp is known as Spathius agrili. For more information about this & the other stingless wasps being used in an effort to lower EAB populations, go to: http://www.emeraldashborer.info/biocontrol.cfm#sthash.cGL7gXXl.dpbs.
Joe Miller March 15, 2013 at 08:13 PM
Cutting out all the Ash trees in town seems analogous to blasting everyone in town with a fire hose because the weather guy says it might rain. And then sending everybody a water bill for it.


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