Jumping Worms

Jumping worms are an invasive species from Asia and have been reported in gardens in Bloomington. They are very difficult to eradicate once established, so preventing their movement and introduction through the movement of soil, plants, and mulch is very important.

There are different species of jumping worms, but they are all in the Amynthas genus and have similar characteristics and behavior. They get their common name from their dramatic thrashing when disturbed as shown in the video below.
Adult jumping worms (Photo by Eric Hamilton, UW - Madison Communications)
This thrashing behavior when disturbed is characteristic of jumping worms (Video from Wisconsin Department of Natural Resources)
The boundary of an area invaded by jumping worms, with the jumping worms' granular castings on the left and uninvaded soil on the right.(Photo by Susan Day, UW - Madison Arboretum)

Why Are Jumping Worms a Problem?

Jumping worms feed on organic matter and break it down very rapidly, consuming nutrients that plants and soil biota need to survive. Unlike other worm species, jumping worms stay close to the soil surface and so aren't effective at aerating the soil. They produce castings that resemble large coffee grounds (shown in photo at left), which provide few nutrients and poor structure for native plants. When native plants start to decline, an increase in invasive plants may be seen.

How Can I Tell If I Have Jumping Worms?

Jumping worms live only one season, and while jumping worms hatch from cocoon-encased eggs in April, they are very small and hard to see at this stage and the clitellum may not be visible.They grow through the summer months, maturing by August. They should be active and identifiable by late May.

First, get the worms to emerge onto the soil surface. Rain or watering an area will cause worms to come to the surface, but you can also apply mustard water (a solution of 1 gallon water plus 1/3 cup ground yellow mustard seed) to make the worms surface. This method is described more fully here. They also do not like vibrations at the soil surface, so even brushing the ground with a broom can cause them to emerge.

Then look for these features:
  • Adult jumping worms have a light-colored smooth clitellum, a band of glandular tissue that completely encircles the worm. European worms have a reddish clitellum that is slightly raised from the rest of the worm body that only partially encircles the worm, like a saddle.
  • Jumping worms tend to be thinner, smoother, and firmer than European worms.
  • One of the best ways to ID jumping worms is by their thrashing behavior when disturbed. European worms wiggle and stretch when disturbed.
Newly hatched jumping worm (Photo by Marie Johnston, UW - Madison Arboretum)
Elements to look for when trying to identify jumping worms (Photo by Linda Tucker Serniak, Oregon State University, and Joanne Schneidermann Dole, Master Gardener).

What Do I Do If I Find Jumping Worms?

  • If you find jumping worms, PLEASE REPORT THEM! You can report them at EDDMaps.org either through the app or on a computer by choosing 'jumping worm (Amynthas sp.)' from the drop down menu. You can also email mciris2022@gmail.com with reports.
  • Take precautions to avoid spreading them. Do not share plants, soil, or compost from infested areas with other gardeners.
  • Remove and destroy jumping worms when you see them. One way to kill them is to put them in a plastic bag and leaving them in the sun for 10 minutes.
  • For more information on jumping worms and possible control methods, visit this Wisconsin DNR website.