Walking through south Minneapolis, I spotted an odd and very purple structure suspended in a tree:
According to the sign, it is an emerald ash borer trap. Mike Schommer, Communications Director of the Minnesota Department of Agriculture, played Q&A with me about the traps. He used to have one on display in his office, but it’s since been deployed to the front lines.
How many traps have been set in Minnesota, and where?
Schommer: I don’t have a number for you, but they try to set them up in a grid pattern around the state, especially where you’re likely to find an infestation. The areas typically are where there’s a lot of human activity, the reason for that is that emerald ash borer often moves new areas when people transport infested material, like firewood.
So you know, a lot of people thought if the emerald ash borer arrived in Minnesota it would be the south eastern part of the state, because it was the closest known infestation – in a town called Victory, Wisconsin. Obviously we’re still concerned about that infestation moving across the river into Minnesota.
We also have state quarantines in Hennepin / Ramsay because of the find in Saint Paul. You cannot move potentially infested materials in those counties.
[This map from the Minnesota Dept. of Agriculture site indicates that two Wisconsin counties are marked as a Federal quarantine; Minnesota's Houston County is under a state quarantine. According to the quarantine notification document (.pdf) a parallel federal quarantine is likely.]
Can you describe how the traps work?
Schommer: The idea is there’s a chemical lure that attracts adult ash borers, and the trap is coated with a sticky material so that when the adults show up and land on the trap, they’re stuck. Workers come by at the end of the season – typically September, when the adults have finished flying – to take the traps down and look for any adult emerald ash borers.
These traps are hung in trees typically, ideally in ash trees. You try and concentrate the traps, as I said earlier, in areas that you’d likely find infestation.
How important is public visibility for a pest field survey?
Schommer: Well certainly the visibility doesn’t hurt. A big part of fighting the emerald ash borer is getting the word out to people about how they can help avoid accidental spread.
We closed the discussion by talking about reach. Schommer stated that the DNR says threre are 937 million ash trees in the state. This is the second year Minnesota set out the purple traps. This year they increased from 350 traps between 1,500 and 2,000.
* MPR News: Federals expected to aid emerald ash borer fight
* Minnesota Department of Agriculture’s emerald ash borer information page