Madison, Wisconsin – Hikers heading to Picnic Point or families walking beneath maples at Olbrich Park are being urged to act immediately if they spot a destructive invasive beetle capable of killing hardwood trees across the Madison area this spring.
According to the U.S. Forest Service and the Wisconsin Department of Agriculture, Trade and Consumer Protection, the Asian longhorned beetle attacks maple, birch, willow, poplar and elm trees. Officials warn the insect tunnels deep into trunks, cutting off nutrients and weakening trees long before visible dieback appears.
Madison’s lakefront parks along Lake Mendota and Lake Monona rely heavily on mature maples for shade and shoreline stability. Similar hardwood stands line trails at the University of Wisconsin Arboretum, Governor Nelson State Park and Devil’s Lake State Park just north of Dane County.
The beetle is glossy black with bright white spots and long black-and-white banded antennae extending beyond its body. Visitors may notice perfectly round exit holes in trunks or sawdust-like material collecting at the base of trees.
If infestations spread, weakened limbs could snap during strong spring wind events common across southern Wisconsin, creating hazards along trails and picnic areas.
Officials urge residents and park visitors to kill the beetle on sight if safely possible and report sightings immediately to state agriculture authorities. Early detection this season could prevent widespread tree removal and protect Madison’s urban canopy into summer.
