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The Mystery Box


July 17, 2011 by wcobserver

Devil's Den Diary

By Megan Webb“What’s that purple box for?”The most frequently asked question at Devils Den State Park is about to be answered. The purple square-shaped box has been hanging in the Ash Tree that lives outside of the pool area. Every person that comes to the pool or store area catches a glimpse of this purple mystery from the branches.Ash trees are beginning to die nationwide from a plague of the horrid emerald ash borers. Emerald ash borer (EAB), Agrilus planipennis Fairmaire, is an exotic beetle that was discovered in southeastern Michigan near Detroit in the summer of 2002. These beetles have migrated from northern China and Korea. They may also be found in eastern Russia, Japan, and Mongolia. The grown adult beetle does little damage; it is the larvae that kill.Courtesy Photo - Adult Emerald Ash Borer, Agrilus planipennis Fairmaire

The EAB, like many insects, has four distinct life stages: adult, egg, larva, and pupa. The larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree’s ability to transport water and nutrients. This causes the tree to shrivel and eventually die. After the tree is infested it starts to slowly decay from the top down. It takes about 3 years for the tree to actually die.

What does this horrible tree killing bug look like? The adult beetle is a bright emerald green with a violet abdomen. It is about ½ inch long. The larvae are a tannish color and remain under the bark until they mature.
The mysterious purple box is no longer a mystery. It is simply an EAB trap that the U.S. Department of Agriculture has put up to monitor for these destructive beetles, which have been found as close as Missouri. Please feel free to look up at the trap. Call our visitor center with questions at 479- 761-3325 or you can do more research on the EAB at this website:



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