Animals are complicated, earthworms are no different. Gardeners, farmers, and soil scientists might see helpful creatures. Those that cycle organic matter, increase microbe activity, and open channels for water to flow. Meanwhile, foresters see a non-native pest of the Midwest. Unwelcome critters fundamentally change how a forest functions by removing its dense leaf layer. However, one type of earthworm, the jumping worm, clearly fits the “bad guy” label, and gardeners need to pay attention to this new species.
Also known as crazy snake worms, these animals are native to Asia but were introduced into North America. They came over the same way as other earthworms before—soil, bait, mulch, or compost. However, in Minnesota, these creatures are relatively new, with the first reports around 2006. They have crawled their way across the state and have been found as close as Northfield and Faribault. No jumping worms have been officially discovered in Le Sueur County as of this writing.
These worms remove nutrients and disrupt the soil’s structure, hurting plant growth. Jumping worm damage will look like someone spilled coffee grounds all over the garden. Be aware that ants or other insects might make nests that resemble coffee grounds too, so be sure to observe closely.
Jumping worms like the upper layers of the soil, so there is a decent chance you may find them digging around. Jumping worms look a bit like nightcrawlers, but the jumping worm will have its “worm band”—called a clitellum—almost flush with their body. The nightcrawler will have a band more like a saddle, not quite wrapping all the way around. Jumping worms also writhe around much more violently when handled, almost leaping out of your hands or container.
Mulch and poorly made compost are prime locations for jumping worms. At least one confirmed sighting in Minnesota was also associated with a bag of mulch purchased from a big box store. If purchasing mulch or compost, ask the seller how they monitor or treat for jumping worms.
Being cautious goes for plant sales as well, especially if a jumping worm was discovered nearby. Look for that coffee ground-like soil in the pot and discuss with the grower your concerns about jumping worms. Bare root plants and plants that were grown in weed-free soil will have the lowest risk of contamination.
Unfortunately, there are no treatments UMN Extension can recommend for jumping worms. One solution that is being researched includes solarization—which uses the sun and clear plastic to heat the soil. Be wary of buying products that claim to cure jumping worms. Currently, no products are registered to do so.
If you think you have jumping worms, please call the Minnesota Department of Agriculture at 651-259-5090 or email your findings to Laura.Vanriper@state.mn.us. You can also call Le Sueur County Extension at 507-357-8230 or email sbugeja@umn.edu. It always helps to have good clear photos of both the soil you found it in as well as a close-up of that band on the worm itself.