Jumping worms, are non-native, invasive earthworms first confirmed in Wisconsin in 2013. Native to eastern Asia, they present challenges to homeowners, gardeners and forest managers. Jumping worms get their name from their behavior. When disturbed, they thrash, spring into the air and can even shed their tails to escape.
This website will help you learn about jumping worms and their effects on yards, gardens and forests, what you can do to prevent their spread and what to do if they’re already on your property.
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Endemic to parts of Asia, jumping worms (Amynthas spp.) first arrived in North America sometime in the late 19th century, probably in imported plants and other horticultural and agricultural materials. Since then, jumping worms have become widespread across much of the northeast, southeast and midwestern U.S. In 2013, jumping worms were confirmed for the first time in the upper Midwest, at the University of Wisconsin-Madison Arboretum.
Jumping worms aren’t the first invasive earthworms in Wisconsin.
Surprisingly, all earthworms in Wisconsin are non-native. There have been no native earthworms in Wisconsin since the last glacier moved through the state thousands of years ago, scouring the landscape down to the bedrock. The familiar earthworms we see in our gardens and on our fishing hooks originated in Europe, brought here by settlers. Although all earthworms can harm landscapes and forests, jumping worms may pose a bigger threat than European worms.
Why jumping worms are a problem
Jumping worms can quickly transform soil into dry, granular pellets with a texture like discarded coffee grounds. This altered soil structure is often unaccommodating to ornamental and garden plants and inhospitable to many native plant species. In addition, they can deplete the soil of nutrients, impact soil organisms, and in many cases, invasive plants thrive where jumping worms live.
- Identification and biology
Where to look for jumping worms
- Jumping worms do not burrow far into the soil – they live on the soil surface in debris and leaf litter, or within an inch or two of the topsoil.
- Look for them in your yard, garden, forest, mulch pile, compost, potted plants and other suitable places.
What jumping worms look like
- Smooth, glossy dark gray/brown color
- Clitellum*, the lighter-colored band, is cloudy-white to gray; completely encircles the body. Its surface is flush with the rest of the body
- Snake-like movement
- They tend to occur in large numbers; where there’s one, there are always more
*The clitellum is a band of glandular tissue composed that partially or fully encircles the worm’s body.
Comparison: jumping worm vs. European nightcrawler
Jumping worm European nightcrawler Brown/gray Pink/reddish Bodies are sleek, smooth and firm Bodies are thick, slimy, floppy Thrash when disturbed; snake-like movement Wiggle and stretch when disturbed. Light colored, smooth clitellum* that is flush with body, relatively close to head. Completely encircles body. Reddish or pink clitellum* slightly raised from rest of the body. Partially encircles body (like a saddle).
When to look for jumping worms
Jumping worms are most noticeable in late summer/early autumn when most of them are fully mature.
Time of year Activity April -May Tiny jumping worms hatch from cocoon-encased eggs. Summer months Worms feed and grow. August – September Mature worms reproduce, depositing egg-filled cocoons into surroundings. Jumping worms are parthenogenic; each worm can reproduce on its own without a mate. First freeze Adult worms die. Winter months Eggs spend cold months protected in cocoons (about the size of mustard seeds!)
It takes 90-120 days between hatching and reproduction. Jumping worms, unlike European earthworms, can complete two generations per year in Wisconsin.
The real problem: cocoons
Unlike most other kinds of earthworms, jumping worms are parthenogenic - they self-fertilize and do not need mates to reproduce. Each new generation begins with the production of hardened egg capsules, known as cocoons, that overwinter in the soil to hatch the following spring. Jumping worm cocoons are resistant to cold and drought and are as tiny as mustard seeds. Since they greatly resemble small bits of dirt, they are hard to see and so are often unknowingly moved in soil, mulch, potted plants, etc.
What jumping worms do to the soil
Jumping worms feed on organic matter in soil, leaf litter and mulch and excrete grainy-looking, hard little pellets, called castings, that alter the texture and composition of soil.
Besides consuming nutrients that plants, animals, fungi and bacteria need to survive, the resulting soil, which resembles large coffee grounds, provides poor structure and support for many understory plants. Invasive plant species may move in when native plants die.
Jumping worm effects on forests
All earthworms, not just jumping worms, can harm forests by changing the soil structure and forest floor vegetation. Their feeding can result in a loss of soil moisture, compacted soil, exposed roots, erosion and an increase of pathogens and non-native plants. The result is less diversity of native plants and animals in delicate forest ecosystems.
There is no “magic bullet” to control jumping worms, at least not yet. Management mainly consists of taking precautions to not move them onto or off your property. However, if they are already there, there are strategies you can use to reduce and slow the spread.
Prevention is by far the best approach to jumping worms. Even if jumping worms are on part of your property, take care not to introduce them to uninfested areas.
The following simple steps will reduce the spread of jumping worms:
- Educate yourself and others to recognize jumping worms
- Watch for jumping worms and signs of their presence
- Arrive clean, leave clean. Clean soil and debris from vehicles, equipment and personal gear before moving to and from a work or recreational area – they might contain jumping worms or their cocoons
- Use, sell, plant, purchase or trade only landscape and gardening materials and plants that appear to be free of jumping worms
- Sell, purchase or trade only compost and mulch that was heated to appropriate temperatures and duration following protocols that reduce pathogens.
What to do if jumping worms are already on your property
- Don’t panic. By taking precautions, you can continue enjoying your yard, trees and garden. Just because you have jumping worms in one part of your property doesn’t mean that they are everywhere. Take precautions to avoid spreading them.
- Remove and destroy jumping worms when you see them. Simply seal them in a bag and throw it in the trash – they will not survive long. Reducing the adult population will eventually reduce the number of egg-carrying cocoons in the landscape.
- Heat treatment. Jumping worms and their cocoons are sensitive to high temperatures. Research has shown that neither worms nor cocoons can survive 104°F or above for more than three days. Under the appropriate conditions and management, compost piles can easily reach this temperature. In addition, using clear plastic to cover the topsoil of gardens and lawns exposed to full sun, can raise the temperature enough to kill cocoons, even in the spring.
- Chemical treatment. Research has shown that the biological insecticide, BotaniGard, can significantly reduce the abundance of jumping worms.
- Experiment. If necessary, try a variety of plants or consider alternative landscaping in heavily infested parts of your property. Try a variety of mulch products such as straw or native grass clippings (e.g. big bluestem, Indian grass, etc).
- Keep your chin up. Research is moving forward to find ways to control and manage jumping worms. As you experiment with controls and adapt your gardening practices, share your successes (and failures) with fellow gardeners, land managers and researchers so that we can all learn from each other!
Identification and Information
Jumping worms - Printable document from the Wisconsin DNR.
Jumping worms: the creepy, damaging invasive you don’t know by Matthew L. Miller, science communicator for The Nature Conservancy. October 2016. This short article serves as a great introduction to earthworms in general and the jumping worm in particular.
Asian jumping worms: what we know, with UW-Madison’s Brad Herrick from AWaytoGarden.com. March 2018. Questions and answers with UW-Madison Arboretum’s ecologist Brad Herrick.
Unwelcome guests: Beware the emergence of dreaded jumping worms by Kathy Stahl, co-chair of the Lower Chippewa Invasives Partnership. A well-written article first published in the Dunn county News on July 7, 2018.
Research Update: Jumping Worms and Sleeping Cocoons by Marie Johnston, postdoc, UW–Madison Department of Soil Science and Arboretum. May 2017. A short overview of recent research on jumping worms at the UW-Madison Arboretum.
Jumping Worm quick facts. by UW-Madison Arboretum. 2022.
Jumping Worms homeowner guide by Jumping Worm Outreach, Research and Management Working Group (JWORM).
Jumping worms in Wisconsin. December 2016 This 40-second video from the Milwaukee Journal Sentinel form December 2016 highlights jumping worms’ distinctive thrashing movement.
Invasion of the Earthworms. September 2011 A two-minute National Science Foundation video that discusses the problems that non-native earthworms cause in forests.
Ralph Nuzum Lecture Series: Impacts of Invasive Earthworms on Forests. A 53-minute talk by Evan Larson, professor of geography at UW-Platteville, discusses the effect of non-native earthworms on ecosystems of northeastern forests.
- Questions and Answers
The Wisconsin jumping worm website is a collaborative effort between the Wisconsin Department of Natural Resources (DNR), the University of Wisconsin-Madison Arboretum, University of Wisconsin-Extension and the Olbrich Botanical Gardens.