YIKES! Invasive Jumping Worms
Jumping worms can harm forests and other areas by disrupting ecological balances and altering
soil. They outcompete established earthworms, and their behaviors can deprive trees and native
plants of necessary nutrients.
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 mid-western 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 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
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.
Jumping Worm Description
||Smooth, glossy dark gray/brown color
||Light colored, smooth clitellum* that is flush with body and completely encircles it.
||Mature worm is 4-5 inches long
||Ravenously on organic matter in soil, leaf litter and mulch
||They do not burrow far into soil — they live on the soil surface in debris and leaf litter.
||Parthenogenetic, producing eggs without the need for a mate.
||They reach maturity within 60 days of hatching; adults do not survive Wisconsin winters
||Thrash violently when disturbed; snake-like movement
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, which 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.
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:
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.
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