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YIKES! Invasive Jumping Worms

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.

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.

The 'clitellum' is a a ring or saddle-shaped region of glandular tissue in the body wall that secretes a cocoon in which the eggs and sperm are deposited for fertilization and development.

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.

Color: Smooth, glossy dark gray/brown color
Clitellum: Light colored, smooth clitellum* that is flush with body and completely encircles it.
Length: Mature worm is 4-5 inches long
Diet: Ravenously on organic matter in soil, leaf litter and mulch
Habitat: They do not burrow far into soil — they live on the soil surface in debris and leaf litter.
Reproduction: Parthenogenetic, producing eggs without the need for a mate.
Lifespan: They reach maturity within 60 days of hatching; adults do not survive Wisconsin winters
Behavior: Thrash violently when disturbed; snake-like movement

The REAL Problem

Unlike most other kinds of earthworms, jumping worms are parthenogeni, 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, and potted plants.

The REALLY bad news is that the cocoons those adults have dropped into the soil do survive Wisconsin winters. It's this ability that allows the next generation of jumping worms to go undetected well into the spring growing season, as tiny cocoons rather than adult worms.

Comparison of jumping worm and earthworm

Test you Knowledge and try this quiz: Earthworm Quiz

Management And Prevetion

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 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:

Graphic of worm clitellum  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.

Further Information on Garden Pests:

 Groundhog Facts and Control
 Japanese Beetle, Facts and Control
 How To Get Rid Of Ants
 All About Aphids and Their Control
 Voles — Both the Good and the Bad