Sep 13 2009

What are those purple panels in the trees?

Published by at 7:10 am under Insects, Fish, Frogs,Trees

I'm back in western Pennsylvania and...

Odd-shaped purple things have been scattered across the state for months but I only learned their purpose recently - and soon they'll disappear.

These gorgeous three-sided panels can be seen from the roadside hanging in trees or on stakes.  At a distance their labels aren't visible but their color is so beautiful and their shape so clean that I assumed the first one I saw was a decoration.  Miles and days later I saw another.  Was this a new fashion?  More miles and days I saw a third.  Rural installation art?

No, these are emerald ash borer traps strategically placed by DCNR to detect the leading edge of the emerald ash borer invasion.  These Asian bugs kill ash trees and there's no cure yet.  The only way to stop them is by quarantine.

Emerald ash borers are not great travellers.  They were first detected in Michigan in 2002 where they probably arrived as stowaways in wooden pallets.  They would have been isolated in Michigan for a long time but humans helped them across state lines by carrying their own firewood and selling infested nursery trees.  That's how the bugs made it to Pennsylvania - in landscaping trees planted in Cranberry Township, Butler County.  We've been under quarantine since they were found in 2007.

Foresters want to know where the bugs are going so they've placed these sticky panels in ash trees to trap them.  The panels don't attract the bugs long distances, just trap them if they're already present.  At the end of the growing season, DCNR will collect the traps and note the locations of emerald ash borers.  Inevitably the bugs will have expanded their range so the quarantine will expand too.

By now the panels have been out there for about four months.  Their colors have faded and their sides are coated in bugs but you might still catch a glimpse of one before they're collected for study.

If the project continues we'll see them sprout again next spring.  This time I'll know what they are.

(photo linked from this article at the University of Illinois Extension)

4 responses so far

4 Responses to “What are those purple panels in the trees?”

  1. Johnon 13 Sep 2009 at 11:57 am

    I’ve seen those in New Jersey, too.

  2. Marjorieon 13 Sep 2009 at 12:59 pm

    They have raised a few questions from a few birders I have heard as to how many other insects do they trap that the birds like to eat? I photographed a pretty little green beetle called the 6 Spotted Green Tiger Beetle at Crooked Creek this summer that looks very much like the Ash Borer, but is not harmful. It was on mud at the outflow. I do hope that they can stop the Ash Borer from doing much more damage. A few friends and I have noticed more of those traps this year than last, so hopefully that will help…it’s “always something” in nature, as well as life in general.

  3. Jasonon 29 Sep 2009 at 8:56 am

    They are all over Northern Virginia. I live in the north western part of the state, with lots of wooded areas. Those traps are all over. I thought they were a new design of bat house, but after reading the article, I learned something new!

    Hopefully, we can do something about these pests.

  4. Barb Simonon 03 Feb 2010 at 12:08 pm

    When I was a girl our family cut down 16 Lombardy poplar trees along the edge of out property. They were all dead – and when the bark cracked off their trunks it was lined with channels that had been eaten by some kind of borer insect. I will never forget it. All those trees killed. Also, lets not forget the chestnut blight. Castanea Dentata – American chestnut – a favorite of cabinet makers and barn builders – gone completely. But in 2000 while on a nature walk I came across a seedling with super long – maybe 7 inches and one inch wide – toothy toothy leaves and my instructor told me it was Castanea dentata. Maybe there’s hope.

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