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DNR invasive species staff

Jumping wormsAmynthas spp.

holding a jumping worm in hand

Adult jumping worms. PhotoL UW Aboretum

Jumping worms, known also as Asian jumping worms, crazy worms, Alabama jumpers and snake worms, are invasive earthworms first found in Wisconsin in 2013. Native to eastern Asia, they present challenges to homeowners, gardeners and forest managers.

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.

Jumping worms get their name from their behavior. When handled, they violently thrash, spring into the air and can even shed their tails to escape.

Click on the following links to find out more:

Introduction
Identification and biology
Effects
Management
Resources
Questions and answers

Introduction

Jumping worms are native to parts of eastern Asia. They were first found in Wisconsin in 2013 in Dane County.

History

Jumping worm on a table

Adult jumping worm. Photo: UW Arboretum

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 grow more rapidly, reproduce more quickly and consume more nutrients than other earthworms in the state. Once jumping worms become established, they 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 many cases, invasive plants thrive where jumping worms live.

Identification and biology

Where to look for jumping worms

Potted plants that may contain jumping worms

Carefully examine soil in potted plants. Bare root stock is best if available.

  • Jumping worms do not burrow far into soil – they live on the soil surface in debris and leaf litter.
  • Look for them in your yard, garden, forest, in mulch, compost, potted plants and other suitable places.
Jumping worm on soil surface

Adult worm on soil surface. Photo: Tom Potterfield

Mulch

Jumping worms thrive in mulch and compost.
Master Gardeners - UWEX

What jumping worms look like

Adult jumping worm

An adult jumping worm.

  • 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 rest of body
  • Bodies are firm and not coated in “slime”
  • 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
Jumping worm Eurpean nightcrawler
Brown/gray Pink/reddish
Bodies are sleek, dry, smooth and firm Bodies are thick, slimy, floppy
Thrash violently when disturbed; snake-like movement Wiggle and stretch when disturbed.
Mature worm 4-5 inches long Mature worm 6-8 inches long
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 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 only 60 days between hatching and reproduction. Jumping worms, unlike European earthworms, can easily complete two generations per year in Wisconsin.

Jumping worm eggs and cacoon

Tiny cocoons are difficult to see – they are the
size of mustard seeds. Photo: UW Arboretum

new jumping worm hatchling

Newly hatched jumping worms are tiny
but grow rapidly. Photo: UW Arboretum

Adult jumping worm

Adult jumping worm.
Photo: Oregon Department of Agriculture

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.

Measuring jumping worm egg size

Jumping worm cocoons are as small as tiny mustard seeds. UW Arboretum

Effects

What jumping worms do to the soil

Jumping worms feed ravenously on organic matter in soil, leaf litter and mulch and excrete grainy-looking, hard little pellets 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 species will move in when native plants die.

Soil ruined by a jumping worm

Jumping worm-infested soil in a potted plant.
Photo: Eau Claire Leader-Telegram

Jumping worm in a potted plant

The characteristic coffee-ground-like soil left
behind by Asian jumping worms.
Photo: Eric Hamilton

Jumping worm effects on forests

Jumping worms effect on woods

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.

See a fun claymation cartoon about the effect of jumping worms on forests from Cornell University.

Management

There is no “magic bullet” to control jumping worms, at least not yet. Management mainly consists of taking precautions to not move them onto your property. If they are already there, you will need to adapt and adjust until there are better control options available.

Prevention

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.
new jumping worm hatchling

Proper treatment of compost and mulch prior to purchase kills
jumping worms and other pests and diseases.
Photo by UW – Platteville.

Plant sales

Plant sales can still be safely conducted,
although extra care and attention must be taken
so jumping worms are not accidentally
moved in soil. Photo by UW – Master Gardeners

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.
  • Experiment. If necessary, try a variety of plants or consider alternative landscaping in heavily infested parts of your property. Keep a log and share your successes with fellow gardeners.
  • Keep your chin up. Research is moving forward to find ways to control jumping worms. Until a solution is found, learn to live with these unwelcome pests.

Other resources

Identification and Information

Jumping worms [exit DNR]. Printable document from the Wisconsin DNR.

Articles

Jumping worms by Bernadette Williams and Colleen Robinson Klug, Forest Health Team, Wisconsin DNR. June 2015. This article gives a general overview of jumping worms in the state.

Jumping worms: the creepy, damaging invasive you don’t know [exit DNR] 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 [exit DNR] 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 [exit DNR] 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

Research Update: Jumping Worms and Sleeping Cocoons [exit DNR] 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.

Statewide jumping worm survey [exit DNR], UW-Madison Arboretum. Complete a short questionnaire about jumping worms.

Fact sheets

Jumping Worm – Amynthas spp [exit DNR]. by UW-Madison Arboretum. Undated.

Jumping Worms [exit DNR] by Cornell University Cooperative Extension. Undated.

Videos

Jumping worms in Wisconsin [exit DNR]. December 2016 This 40-second video from the Milwaukee Journal Sentinel form December 2016 highlights jumping worms’ distinctive thrashing movement.

Invasion of the Earthworms [exit DNR]. 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 [exit DNR]. 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.

FAQ

FAQ [PDF]

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.

Last revised: Monday September 17 2018