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Emerald Ash Borer infestation on Madison’s south side

The City of Madison Forestry Section has confirmed an Emerald Ash Borer infestation on Madison’s south side at Doncaster Park, 4341 Doncaster Drive, Madison. This infestation site is the first on Madison’s south side and adds to previous finds on the City’s north side at Warner Park, multiple finds thru the east side following closely along I-90 and on the City’s west side along the border with the City of Middleton.

"While it's disappointing to have found EAB in a new location within the city it is not surprising, given the ease with which this pest can hitchhike with the help of humans," said Eric Knepp, superintendent of Parks Division.

The Parks Division recommends that property owners who have ash trees in their own yards:

  • Keep a close watch on ash trees for signs of possible EAB infestation: Thinning in the canopy, D-shaped holes in the bark, new branches sprouting low on the trunk, cracked bark, and woodpeckers pulling at the bark to get to insect larvae beneath it.
  • Consider preventive treatments if your property is within 15 miles of a known infestation. Visit our homeowners toolkit which includes a helpful decision making guide on whether to chemically treat your ash trees. Treatment costs vary depending on size of the tree and whether you do the treatments yourself or hire a professional.
  • When replanting, consider planting a variety of tree species that are not susceptible to EAB.
  • Call a professional arborist for expert advice, and visit for detailed information.

Madison Parks Forestry staff made the find by keying in on heightened woodpecker activity in the ash trees within the park. Woodpeckers will eat emerald ash borer larvae that are under the bark this time of year. This usually happens higher in the tree where the emerald ash borer prefers to attack first. If there are large numbers of larvae under the bark the woodpecker damage can make it look like strips of bark have been pulled off of the tree. This is called "flecking."

Emerald ash borer is native to China and probably entered the United States on packing material, showing up first in Michigan about 10 years ago. It was first found in Madison in 2013 in Warner Park. EAB adults lay eggs on the bark of ash trees in mid to late summer. When the eggs hatch a week or two later, the larvae burrow under the bark for the winter and eat the wood, forming the characteristic S-shaped tunnels and destroying the tree's ability to take up nutrients and water. In summer, the adults emerge through D-shaped holes in the bark.