What thrashes and is taking over the Midwest? Jumping worms
Kelly Frampton had recently moved to her new home in the country outside Eudora, Kansas, when she noticed a strange looking worm on her property.
“I'm trying to tell myself it's another earth worm, but they're just so different from a regular earthworm,” said Frampton.
She brought it to K-State Research and Extension who confirmed that it was a jumping worm, also known as Alabama jumper or Asian jumping worm. It’s an invasive species originally from Asia that has been popping up in states in the Midwest in the past few years.
Unlike other earthworms — which are also not native to the region — these worms are not good for the soil. Jumping worms have a voracious appetite, feasting on the leaf litter in gardens and forests and depleting nutrients in the soil. Sometimes they can even eat the roots of the plants.
“It was depressing for a few days there. I had just gotten moved out to the country and had all these plans for this big, beautiful garden,” Frampton said. “And I was like, oh, I'm not even gonna be able to plant anything.”
The worms’ excrement changes the structure of the soil to what looks like coffee grounds or taco meat, which makes it harder for the soil to hold water and for plants to take root. Jumping worms also are known to push out other earthworms that are good for the soil, although it’s not yet known exactly why this happens.
A jumping worm can be identified by its firm skin and white band around their body, but the most noticeable characteristic is the thrashing behavior that gave it its name.
“Everybody calls 'em creepy and they are just kind of a creepy worm," Frampton said.
They typically live in the top 3-4 inches of the soil. The Illinois Extension suggests testing for worms by pouring a gallon of water with 1/3 cup of ground yellow mustard seed mixed in on the soil. This should drive the worms to the surface to be identified. They can be killed by placing them in a plastic bag and leaving it out in the sun.
‘Dying for information’
Jumping worms have been in the United States for about two centuries now. They only spread to the Midwest in the last 10 years. They have existed in the deep south for at least 30 years but they are less of a concern in states such as Louisiana that have other invasive worms to worry about.
Although these worms seem to be everywhere, there hasn’t been much research about their impacts or how to manage them, leaving gardeners without much assistance when it comes to saving their plants.
“If someone wanted to do the research, I could have many yards and really willing homeowners who would allow people to come into the yard to treat it or do experiments,” said Jody Green, an entomologist at the University of Nebraska Extension who has been receiving calls about the worms.
Much of the current research comes out of the University of Wisconsin-Madison Arboretum. Bradley Herrick, an ecologist and program manager at the arboretum, was part of the group that found the first confirmed case of jumping worms in Wisconsin back in 2013. Since then the arboretum has been doing research and outreach about jumping worms.
“We've gotten hundreds and hundreds of requests from regular people, gardeners that just want information. They're just dying for information,” he said. “And so we are doing our best to synthesize research, conduct research and then make sure that we get that information back out to people that can use it.”
Later this year, Herrick is going to look into the worms’ potential impact on agriculture at farms in Dane County, Wisconsin. He said the worm's effect on crops is a big gap in their knowledge about jumping worms.
“Are they present? What's their abundance? And if they are found in ag soil, is it because there's a source at a nearby forest that they’re in and they’re moving out into the ag field?” he said.
The worms are probably more likely to be in no-till fields. A potential problem they could pose for farms is displacing the earthworms that are good for the soil.
In terms of management, some of the arboretum’s research does show that the worms’ cocoons will not hatch if they are exposed to temperatures of around 100 degrees for at least three days.
“We know that heat will work. Now it's kind of looking at how do we implement that?” said Herrick.
One option is using controlled fires to manage the population in forests or gardens. Another is solarization, a method that entails covering the soil with plastic to heat it up using the greenhouse effect.
‘We have to coexist with them’
Anecdotally, some farmers are having success experimenting with ways to manage the worms. The Facebook group, Invasive Jumping Worms: Observation and Discussion Group allows those who have found them in their gardens to share how they’ve managed the worms and ways to get rid of them.
Lucinda Zmarzly, a math teacher in Lincoln, Nebraska, kills the worms using a weak vinegar solution. She also uses fertilizer made from tea seed meal to keep them away, which is a method used to keep worms off of golf courses.
Even so, she has had them in her garden for the past four or five years. The eggs survive through the winter and the fully-grown worms appear again every summer.
“I've gradually accepted that I'm never gonna get rid of the worms,” she said. “I've accepted that we have to coexist with them.”
Learning how to coexist with jumping worms is also a question that Herrick is considering in his research.
“How do we move forward with this, yet another invasive species, and maintain biodiversity and ecosystem services and function? Those are some of the things that we don't know yet, but we're hoping to work on,” he said.
The Missouri Department of Conservation also suggests helping to stop the spread by not buying jumping worms as bait for fishing, cleaning digging equipment before transporting it and inspecting nursery plants for cocoons before planting them.
This story was produced in partnership with Harvest Public Media, a collaboration of public media newsrooms in the Midwest, and the Mississippi River Basin Ag & Water Desk.