What are invasive jumping worms and what threat do they pose to Michigan?

Worms change composition of soil

Entire jumping worm (Metaphire hilgendorfi), including flat, milky clitellum near head (closer to bottom of photo) (Photo courtesy of Holly Greiner-Hallman, Oakland University.)

Jumping worms look similar to earthworms but can easily be identified because of the way they thrash around.

The worms have been detected in Michigan and pose a threat to the ecosystem because of the amount of leaf litter they consume.

They were first recorded in 2008 in Oakland County and officials suspect they could be widespread throughout the lower peninsula.

They can reproduce without a mate and eat large amounts of leaf litter, destroying the important organic layer while out-competing native species.

When they eat organic matter, they also change the composition of the soil which can make it less hospitable to natural fungi, bacteria, and plant growth. It can impact the native plant growth in forests and harm ornamental plants and turf in lawns and gardens.

Read: Let’s talk about Michigan’s invasive trees and shrubs: How to identify them and the threat they pose

How to identify a jumping worm

Michigan officials have shared a list of identifying features of a jumping worm.

  • 1.5″ to 8″ glossy gray to brown worm.
  • Distinctive jumping or thrashing behavior and snakelike movements.
  • Body is firm and shiny.
  • Clitellum (smooth, wide collar) is flat and goes all the way around the body.
  • Worm castings create uniform, granular soil similar to coffee grounds.
  • Overwinters in 1-2 millimeter cocoons; only one worm is needed to produce many cocoons.

How to test for jumping worms

Jumping worms spread through the mulch, compost, potted or balled and burlapped plants, translating or through bait release. Community compost and mulch piles have the potential to spread jumping worms.

You can use a liquid “mustard pour” to test your soil for jumping worms. Mix 1/3 cup of ground hot yellow mustard seed into one gallon of water and pour half of the liquid slowly over one square foot of the soil you want to test.

Wait a few minutes and pour the rest of the liquid. That will make worms (any earthworms) come to the surface. Collect any jumping worms you find. The mustard solution will not harm plants or kill the worms.

How to kill jumping worms

There are currently no proven methods to control or manage populations of jumping worms. Individual worms can be killed by being placed inside a sealed plastic bag and then freezing, heating or sending the bag to a landfill.

If you have jumping worm cocoons in your mulch or soil the best way to kill them is to heat the mulch or soil to 130 degrees Fahrenheit for at least three days.

The best way to prevent the spread of jumping worms is to clean your shoes, vehicles, and gear when moving from site to site. You should also only purchase new soil, bare-root plants, or mulch that doesn’t contain jumping worm cocoons. Do not use jumping worms as bait or composters.

How to report jumping worms

Click here to use the Midwest Invasive Species Information Network online reporting tool.


About the Author:

Kayla is a Web Producer for ClickOnDetroit. Before she joined the team in 2018 she worked at WILX in Lansing as a digital producer.