Invasive jumping worms. source: State of VT Agency of Agriculture Food and Markets

Many of us grow up learning that worms are good for the soil. While earthworms do provide important benefits—like breaking down organic matter and releasing nutrients—not all species of earthworms are beneficial. Some can actually harm soil. Jumping worms, also known as crazy snake worms, crazy worms, snake worms, or Asian worms, are an example of an invasive worm that hurts soil health.

Jumping worms are aptly named. When disturbed they thrash wildly and can shed their tails. They look different than other worms we have in Vermont. The body of the worm has a smooth, glossy dark grey color and their clitellum (the thick, lighter-colored tissue around the body near the head) is cloudy-white to gray and completely encircles the body. Its surface is smooth and flush with rest of body. They live close to the soil and, depending on the species, can be anywhere from one to eight inches long. You may also be able to identify an area with jumping worms by the appearance of the soil. As worm castings accumulate, the soil begins to look grainy, like coffee grounds.

Vermont has no native earth worms. This is because the entire state was covered by a glacial ice sheet approximately 12,000 years ago, which would have removed any worms that had evolved along with our forests. All earth worms we see here today were imported from Asia or Europe along with plants and soil. You may ask, why is the jumping worm any different from these other non-native worms?

Jumping worms outcompete other species and negatively alter soil health, causing changes in soil temperature, moisture, and chemistry. They are heavy feeders, consuming large amounts of plant seeds, insects, and other organic matter very quickly. They also reproduce quickly. As they consume the organic material of a forested landscape, they reduce the leafy understory of a forest. As the leaf litter disappears, soil erosion increases, and the roots of trees can even become exposed. This in turn affects the entire habitat health and diversity of the forest. In your garden, plants may show signs of wilting despite adequate moisture, and you may find you need to apply compost and fertilizers more often or more heavily to achieve the same results.

The best time to spot jumping worms is from June to September. Adult worms die off every winter, but their cocoons overwinter in the soil and hatch the following year. To identify jumping worms in your soil, mix a few spritzes of dish soap into two gallons of water. Pour the solution slowly over the soil, which will drive worms to the surface. You can then inspect to see if you have regular earth worms or jumping worms. If you find jumping worms, you can kill them by soaking them in rubbing alcohol, leaving them in a bucket of soapy water for a few hours, or freezing them. Just remember that killing the worms will not get rid of the cocoons that will hatch next year. You can also try “solarizing” a section of earth, using sunlight to increase soil temperatures. This method involves heating the soil by covering it with clear plastic for four to six weeks during a hot period of the year, allowing it to be exposed to steady sunlight.

The best thing you can do is prevent jumping worms from “jumping” between locations. If you don’t have them, do your best to avoid then. You can test potted plants you buy by pouring a mixture of 1/3 cup mustard powder and 1 gallon of water into the pot. This will make any worms come to the surface and will not harm the plants or worms. You can then check for jumping worms. This is only a rest for adult worms and will not help prevent the spread of eggs and cocoons. Avoid importing wood chips, mulch, or compost onto your property unless it is heat-treated to 130°F for at least three days.

What you can do:

• Learn to identify jumping worms and report sightings of jumping worms on the iNaturalist website: www.inaturalist.org
• Avoid practices that spread earthworms into untreated soil or compost:
• Nursery plants and trees with root balls should be inspected before planting. 
• Plant bare root stock or seeds when possible.
• Do not buy jumping worms for composting, vermicomposting, gardening or bait.
• Clean your shoes and equipment in between home, work, and recreation.