Madison Reporter

MADISON, Wis. – The City of Madison Engineering Division welcomes volunteers to help with protecting oak trees on City property, which are showing signs of spongy moth activity and stress. Engineering will provide free burlap for volunteers.

Spongy Moth caterpillars feed on many tree and shrub species, preferring oak, aspen, birch, crabapple, willow, tamarack and basswood (linden). Populations periodically become very high when weather conditions are favorable for the insect. During these “outbreaks,” caterpillars can defoliate numerous tree and shrub species, create a tremendous nuisance, and cause skin rashes and other irritation. The Wisconsin Department of Natural Resources (DNR) warns the public that the next two months could bring the worst spongy moth caterpillar outbreak in more than a decade.

Get Involved 

The City has reports of spongy moth  impact in areas specifically along the west and near west side of the City (see map). If anyone is interested in helping the City respond to spongy moth, get involved by doing the following:

 •    Pick up burlap from the City for free between 8 a.m.-4 p.m., July 8, 2023, at Engineering Division Operations Facility, 1600 Emil Street, Madison, Wis. The City has five rolls of 100 yards available, and will have material available until it runs out.

•    Email City of Madison Engineering Division at ENLand@cityofmadison.com and include your name, phone number and description or  a map screen shot of where you are seeing the impacts or planning to work prior to picking up any materials.

•    If you don’t want to volunteer but see infestations, please email ENLand@cityofmadison.com to report for tracking purposes.

•    Volunteers will be asked to install burlap, daily check and destroy caterpillars, and then remove burlap in August from the trees.

•    Instructions for installing burlap can be found at UW Extension.

•    Destroy any adult pupae and adult females as recommended by the UW Extension instructions. You are also welcome to squish any spongy moth caterpillar  you see under your shoes as each caterpillar removed is one less that can help continue the outbreak (but please be mindful not to touch them with your clothes or bare skin due to the potential irritation they can cause)

•    Do not use any chemicals or employ any other methods. At this time, the City only asks for help with burlap installation and removal, checking, removals, and monitoring. 

•    Let the City know if you notice spongy moths in ponds or greenways outside of the included map. Please email any ponds or greenways where you see impacts and evidence of spongy moth. You can find information on what to look for in the links provided by Forestry’s website: https://www.cityofmadison.com/news/how-to-help-your-trees-during-the-spo...

Those who find spongy moth caterpillars should avoid touching them with bare skin as the hairs often cause a  rash, welt or other irritation. Rubbing alcohol can help to remove the hairs and chemical irritants from skin that is exposed to the hairs.

The caterpillars are large right now and nearing the end of their feeding. We likely will see improvement to the trees in the next few weeks.  This volunteer work will contribute in part to reduced numbers of species, but will not eliminate them. Engineering can use data from the volunteers to assist in evaluating the extent of spongy population if necessary.  In most cases these trees will come back. However, given the recent drought conditions, any assistance from volunteers is appreciated. 

Original source can be found here.