A new invasive species in Illinois may prevent vigilant gardeners from sharing divided perennials. Jumping worms, also called crazy worms or snake worms, are species of earthworms that deplete nutrients in the soil which in turn affects plant growth. Jumping worms are being reported in several counties in Illinois, and continue to spread through the movement of soil, compost, and mulch.

Much to the dismay of generous gardeners as well as organizations selling shared perennials, spread of this invasive species can also happen quickly through dividing and moving perennial plant species. Spring is often the time of plant sales and sharing perennials, this practice can be harmful to private yards and gardens, as well as forested land. 

About Jumping Worms

Jumping worms (Amynthas spp.) are similar to earthworms but with devastating effects. They are native to Asia and likely brought stateside in potted plants, landscape material, and other horticultural material.  

Identification

• Jumping worms will become rigid and actively thrash when disturbed, lending to their name. 
• They may also drop their tail as a defense mechanism. 
• They are 4 to 8 inches long and darker on top than bottom.
• The key identifying feature on the jumping worm is a smooth, milky white band called the clitellum. The clitellum of a jumping worm is flat and encircles the body; on a common earthworm, the clitellum is raised and does not encircle their body, but rather sits like a saddle. This feature is easily seen and different from any other earthworm, making it identifiable in the landscape. 

Impact

Jumping worms can negatively impact landscapes by depleting available nutrients, damaging plant roots, changing soil structure, even altering the water-holding capacity of soil.

Jumping worms swarm in large groups and reproduce in multiple ways. In addition to sexual reproduction, asexual reproduction makes it possible for a single worm to reproduce without a mate. When the population becomes high enough, they become destructive to plant roots in addition to soil. Although the adults die over winter, they leave behind cocoons with eggs inside that are imperceptibly small. Eggs hatch in spring and can reach maturity in 60 days.   

Though most earthworms in the garden are non-native and break down organic matter in our forests, jumping worms perform this task at an alarming rate. This invasive species has spread quickly. Illinois first reported jumping worms in 2015, and just four years later they are reported in 16 counties and suspected in eight more.  

Many gardeners may consider worm castings as beneficial to garden soil. However, jumping worms break down organic matter so quickly that nutrients are added at a rate too fast for plant uptake. Since the worms perform this task in the top layer of the soil profile, it can also lead to soil becoming too dry. Depletion of topmost organic matter can also inhibit other beneficial soil microbes in addition to the depletion of nutrients for plant growth.   

Symptoms

The castings are another good identification technique that can be used during winter. Jumping worms do not tunnel in the ground like other earthworms, they move through the top 2-4 inches of the leaf litter and devour it leaving behind their castings that look like coffee grounds. The castings left behind will be uniform as opposed to random piles left behind.  

Management

Once invasive species populations establish in an area, they can be difficult, costly, or even impossible to eradicate. Native plants, animal, forests, waterways, and even native soils can be devastated by non-native and invasive species and their migration. Educational outreach is our best chance at preventing their use and spread.

There is currently no control for jumping worms beyond prevention. Because this species is relatively new to Illinois, accurate counts are difficult due to the species likely being underreported. Most homeowners are unaware of the presence of jumping worms until they actively look for them. How this species will affect nurseries, mulch production, and yard waste collection has yet to be determined.  

Stop the spread of jumping worms by following these practices: 

1. Be aware. In summer jumping worms will be easy to find because they will be above the soil in the leaf layer.  If you see earthworms early in the spring, they are not likely jumping worms.  
2. Investigate your yard or garden using a third cup dry mustard powder with a gallon of water. Remove leaf layer to get to soil surface and pour half of the solution into soil. Jumping worms will come to the surface almost immediately. This practice will not hurt plants. 
3. Place any adult jumping worms found into a sealed plastic bag then in the trash.  
4. Clean hiking boots, landscape equipment, and garden tools   
5. Do not transfer soils or plants. Most potting soils and organic matter amendments from garden centers are safe and been pasteurized or raised to a temperature that kills the cocoons.  
6. Discourage plant swaps and plant sales of home-grown plants. Annual plants sales can function by sourcing plants through wholesale nurseries.  
7. Produce compost on-site and ensure it reaches temperatures of 131 degrees.  
8. Do not use as fishing bait and do not dump your fishing bait.  
9. Educate yourself and others.
10. If you suspect, please contact the University of Illinois Plant Clinic at plantclinic@illinois.edu or 217-333-0519. Please include an image for identification.  

Learn more about Illinois invasive species. 

More Resources

• Jumping Worms factsheet, University of Illinois Extension
• Video: University of Illinois Extension, Richard Hentschel
• Video - Worms in the Garden: University of Wisconsin Extension, Joey Baird
• Video - Invasive Jumping Worms Seminar: University of Wisconsin, Brad Herrick
• Video - Jumping Worms in Minnesota: University of Minnesota, Angela Gupta

ABOUT THE AUTHORS 

Kelly Allsup is a Horticulture Educator for University of Illinois Extension serving Livingston, McLean and Woodford Counties. She meets the educational needs of her community, including local chapters of Master Gardener and Master Naturalist volunteers, through expertise in home horticulture and entomology. Her passion for ecologically-friendly gardening and all things plants makes her a dynamic speaker on topics that range from beneficial insects, growing vegetables and fruits, to urban trees.

Sarah Vogel is the Horticulture and Natural Resources educator for DeWitt, Macon, and Piatt Counties. She specializes in annuals and perennials, greenhouse production, landscaping, and urban forest management. She received a bachelor’s degree from SIUC in Forestry with a concentration in recreation management, and a master’s degree from UIUC in Crop Sciences with a concentration in Horticulture. Sarah’s passion is connecting with underserved populations in the community and fostering an appreciation for nature through education.