Dan Brown just needs to scrape the surface of the soil with his hand before they emerge – worms that wriggle so rapidly they’ve been dubbed jumping worms.
“You’ve heard of Wally World? Welcome to Wormy World?” Brown joked when a reporter arrived to see the jumping worms he discovered in his yard in the Cherry Hill subdivision of New Lenox.
“I don’t know how I got them. My best guess is they were in a bag of mulch I bought,” Brown said.
He first spotted them in September.
But jumping worms have been around northern Illinois since 2015, although Will County has not yet been identified as a location for the invasive species, according to the University of Illinois Extension Service. Native to Asia, they were first found in the U.S. in Wisconsin in 2013.
They don’t really jump, although Brown said one was thrashing about so vigorously that it lifted itself slightly off the patio surface after he tossed it aside.
“They get they name from their body reaction if you try to pick them up and move them,” said Nancy Kuhajda, master gardener at the University of Illinois Extension Service office in Joliet. “They wiggle around a lot.”
Whether they pose any danger is still to be determined, Kuhajda said. While the worm is not native, neither are the other worms found in Illinois, she said. They all came from Europe.
Brown suspects the creatures have been destroying his lawn. He can scrape up portions of grass with his hand and find the worms below.
“They live about this far from the surface,” Brown said, spreading his thumb and index finger a couple of inches. “They pulverize [the dirt], and the grass can’t grow.”
Kuhajda said the jumping worms’ presence is coincidental with the lawn damage. More likely, Brown has grubs, she said, because jumping worms do not eat grass roots, but grubs do.
But jumping worms can turn soil into the texture of discarded coffee grounds, according to the Wisconsin Department of Natural Resources website. Brown’s soil has such an appearance where the worms are found.
The University of Illinois Extension Service “Invasive Species Alert” on jumping worms includes the following warning: “Populations of jumping worms have the potential to change the soil structure, deplete available nutrients, damage plant roots and alter water holding capacity of the soil.”
Kuhajda said those potential problems are related to the worm’s appetite for organic matter and its rapid reproductive rate, creating a particular threat in forest areas.
“They tend to eat the top one to three inches off the forest floor,” she said. “They reproduce incredibly quickly – far more quickly than other worms. They have the potential to eat up all material off the forest floor.”
Therein lies the threat.
“The concern is that because they would be eating so voraciously and multiplying so rapidly the actual structure of the soil would change,” Kuhajda said.
The jumping worms have not yet been detected in the Will County forest preserves, according to a spokeswoman for the Forest Preserve District of Will County.
Will County has not been put on the Extension Service map of affected counties because the worms have not been detected in sufficient numbers, Kuhajda said.
The Extension Service encourages anyone who finds the worms to contact the agency so it can track the movement of the species. The phone number for the Joliet office, which serves Will County, is 815-727-9296.