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Politics & Government

Emerald Ash Tree Borers On the Move

County foresters monitor pests with giant purple traps

What are those mysterious giant triangular purple receptacles hanging from trees all over Fairfax County?

Wes Kovarik, a hiker along Difficult Run said, “I think it’s for stink bugs.”

Kristen Mears of McLean said, “I think it’s some kind of insect trap.”

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David Flessas of McLean thought they might be for bag worms.

The answer: they are emerald ash borer traps.

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Emerald ash borers are insidious insects that decimate ash trees.  First discovered in Fairfax County in 2008, these pests migrated from Asia – specifically China, Korea and Japan. To date, they have killed more than 25 million ash trees in the United States.

Fairfax County, the U.S. and Virginia Departments of Agriculture in tandem with Consumer Services have instituted a statewide survey. Beginning April 26, 500 emerald ash borer traps have been hung throughout Fairfax County to identify and monitor areas of infestation.

These traps are non-toxic. Although they do not contain any chemicals or pesticides, they are covered in extremely sticky adhesive. Fairfax County has asked people to report any fallen traps and advise not to touch them. Fairfax County Forest Pest Branch can be reached at 703-324-5304.

Emerald ash borers have been found in many Virginia and Maryland suburbs. The primary cause for migration is the movement of firewood as the borers can live up to one year in a log. To prevent the spreading of the borers, state and federal governments have announced quarantines banning the transportation of firewood out of Northern Virginia. Brian Worthy, Public Information Officer for the Fairfax County Office of Public Affairs advised campers to use local sources of firewood. The following areas are covered by the quarantine:  Fairfax County, Arlington County, Clark County, Fauquier County, Frederick County, Loudon County, Prince William County, and the cities of Alexandria, Fairfax City, Falls Church, Manassas, Manassas Park and Winchester. According to the Fairfax County Government, violation of these quarantines can result in fines up to $250,000.

The motto of the foresters is, “Don’t move firewood. Buy it where you burn it.”

Joan Allen, an Urban Forester II with the Urban Forest Management Division of Fairfax County, is one of the individuals responsible for hanging traps. She tries to hang them on trees in both residential and wooded areas, but she said, “We need landowners’ permission to hang on their property. People are at work so we put up a lot in parks.”

People often approach Allen and ask about the traps because they are so conspicuous. Most think they are for stink bugs, mosquitoes or bats. 

Traps are designed specifically for the ash tree borers. They are purple because the borers have been found to be attracted to that wave length of color. The inside of the traps are lined with a lure that is made up of the same chemical ash trees emit when under stress.

Stressed trees are an easy target.  A tree in the middle of a parking lot is a more likely victim than a tree in the forest. Therefore, according to Allen, all sightings have been in residential areas as opposed to woodlands.

Allen has been tracking the borers for some time. She said, “I’m surprised it hasn’t spread faster. When it started in the Midwest, it seemed like it was spreading all over the place…The first sightings [in Fairfax County] were in Herndon, Newington and Fairfax Seven Corners. They stayed around there for two to three years. Now there are a few new spots here and there. Last year they were first discovered in Prince William County.”

For concerned homeowners with emerald ash trees, there are two signs of borer infestation:

  1. Trees may have horizontal splits or fissures in their bark.
  2. Trees may have small shoots or branches growing from the trunk, called epicormic shoots.

County officials have stated that all ash trees are at risk of infestation since the emerald ash borer has been sighted throughout Fairfax County. The time to take action is May through June:

  • Use an insecticide containing the chemical imadacloprid.
  • For larger trees, trunks greater than 15 inches, a professional tree care firm is advised.
  • If a tree has lost more than 50 percent of its leaves, there are no treatment options as insecticides will probably not work.
  • Insecticides applied by homeowners need to be repeated annually, professional treatments every three years.

For more information: http://www.fairfaxcounty.gov/news/2011/updates/emerald-ash-borer-traps.ht

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