Gardening Harmful animals

Jumping Worms: The Upcoming Environmental Disaster

Jumping worms: not your average passive earthworm! Click to see what I mean! Video: Wisconsin DNR 

In the recent blog article Earthworms are Bad News for North American Forests, I wrote about the problem of invasive European earthworms in North America and the damage they are doing to forests, but that may be only be the start. Ecologists are even more concerned about a co-invasion from three newer introductions: Asiatic jumping worms (Amynthas agrestisA. tokioensis and Metaphire hilgendorfi), also called snake worms or crazy worms. 

map of jumping worm distribution in Northeastern North America
Fairly recent map of jumping worm distribution in Northeastern North America. Photo: http://www.eomf.on.ca

They seem to have been introduced accidentally into the southeast United States in the 19th century, probably through contaminated nursery stock imported from Japan or Korea. But they’re spread into the North seems recent, within the last 15 years. They’re already present in all Northeastern US states and lately seemed to have pushed across the Midwest showing up here and there and now across the Rockies into Oregon and to have jumped the border into Ontario, Canada, although their presence is still very sporadic throughout this vast territory. 

What Are They?

Single jumping worm on ground.
Jumping worm. Photo: Josef Gorres, University of Vermont

Jumping worms are large, plump earthworms, up to 8 inches (20 cm) in length, looking much like the common earthworm (Lombricus terrestris), also called nightcrawler or dew worm, but with a startling habit: they jump and thrash when disturbed! They’re very animated and tend to remain on the soil surface. Their subsequent movements are snakelike rather than wormlike, as they slither from side to side. As for why they’re called crazy worms, well, I think any earthworm that jumps when you bother it is likely just a bit crazy, don’t you? 

They’re not just present in northeastern North America. They’ve become established many other parts of the world. In the southeastern US, where they’ve been around for more than a century, they may be called Alabama jumpers or Georgia jumpers. In Europe, when they are also now present and spreading rapidly, a different series of Amynthas species seems involved.

How to Recognize Them

Comparison between nightcrawler and jumping worm.
The jumping worm has a smooth, light-coloured ring around its body compared to the raised, ridged, pink ring of a nightcrawler. Photo: EarthwormWatch.org

If jumping and thrashing isn’t enough warming that these are not your average earthworms, look at the clitellum, the “ring” earthworms have around their body. That of the jumping worm will be smooth and light-colored, sometimes almost white, not almost the same color as the rest of its skin as that of the nightcrawler, and almost flush with the skin rather than bulging and ridged. They’re dark worms, almost gray in color, with a glossy smooth skin. They will occasionally lose their tails as a defense mechanism to escape predators.

Jumping worm castings with single cocoon.
Jumping worm castings with a single cocoon. Photo: Marie Johnston

Jumping worms don’t dig tunnels, nor do they feed underground, but remain near the top of the soil, in the top few centimeters, feeding on leaf litter. Instead of leaving their excrements in little piles of castings as is typical of nightcrawlers, they cover the soil surface with dry, grainy, pellet like castings that look somewhat like dry coffee grounds, keeping seeds from sprouting and destabilizing soils.

They are best recognized in late August and September, when they have reached their full size.

Life Cycle

Unlike nightcrawlers, which can live 6 years or longer, jumping worms have an annual life cycle. The adults die in late fall, but leave tiny cocoons, difficult to spot, that overwinter. They have been known to survive temperatures as cold as -40˚F/C. They grow quickly in the spring, outcompeting and often eliminating other earthworms. Hermaphroditic, they can reproduce sexually, but also parthenogenetically, producing cocoons without fecundation, so it takes only one to start a new colony. There are two generations per year (three in mild climates).

One beacon of hope is that they seem to prefer neutral and alkaline soils to acidic ones, which could help slow their invasion some areas.

⚠️ Warning: Jumping worms are considered a prohibited invasive species in several US states and it is illegal to possess them with the intent to sell, import, purchase, transport or introduce them. 

Damage Done

Forest floor damaged by jumping worms: almost nothing is growing.
Forest floor damaged by jumping worms. Photo: UVM

Jumping worms live in denser numbers than regular earthworms and thin the layer of forest litter (duff) at a speed unknown in other earthworm species, reducing it by 95% and leaving the soil essentially bare. The degradation of the litter is so rapid that the nutrients released cannot all be absorbed by the soil and plant roots. It’s like a fast-release fertilizer instead of a slow-release one and results in the impoverishment of the upper layers of soil, the compaction of lower layers and the pollution by nitrogen and phosphorous of nearby bodies of water.

Jumping worms also consume plant seeds and rob the soil seed bank of its reserves. As a result of that and of the environmental degradation they cause, the forest floor becomes depauperate in plant species. Native species, dependent on thick leaf litter are eliminated, mostly replaced by invasive exotic weeds. They are equally damaging in forest and prairie environments. 

Animals are likewise affected. Salamanders and many bird species will not eat jumping worms, spitting them out or avoiding them after an initial tasting. Ground-nesting birds disappear. However, moles will eat them, so can be helpful in controlling them.

How to Avoid Jumping Worms

Pamphlet on jumping worms.
In many areas, such as in Wisconsin, pamphlets are available to help gardeners identify the pest. Photo: hngnews.com

It is believed the current sporadic diffusion of jumping worms into northeastern North America has been largely caused by the transport of contaminated nursery stock and by their use in as fishing bait. For that reason, the following control methods can be helpful:

  • Pay careful attention when sharing and moving plants. Always check for worms. Buy bare root stock when possible. 
  • Clean compost, soil and debris from vehicles, personal gear (including boots and shoes), equipment and gardening tools before moving to new sites. 
  • Do not buy or use jumping worms for bait, vermicomposting or gardening. 
  • Only purchase compost that has been heated to appropriate temperatures for a sufficient duration. 
  • Dispose of any live worms in the trash or place them in a bag and leave them out in the sun for at least 10 minutes. Then throw the bag away. Likewise, dispose of any fishing bait responsibly.
You can used a mustard solution to check for crazy worms. Ill.: iMapInvasives
  • Check your property for earthworms using a mustard solution. (Don’t worry, it’s harmless to plants!) Mix a gallon (4 liters) of water with 1/3 cup (80 ml) of ground yellow mustard seed and pour slowly into the soil. This will drive any worms to the surface. If you discover jumping worms, avoid moving plants or soil from your yard. 

How to Control Jumping Worms

There is presently no viable control method for jumping worms, although studies are being carried out on possible repellents and pesticides, notably dousing the soil with products containing saponins, such are tea seed meal, and prescribed burning. Presently, the only effective control is preventing their spread.

You may not have jumping worms in your garden yet and, if so, that is a state you’ll want to maintain. Keep an eye out for this new invader!

Video: Wisconsin DNR


Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

19 comments on “Jumping Worms: The Upcoming Environmental Disaster

  1. Do they eat southren pine needles?
    If so I do not have them here in Middlands of South Carolina.

  2. Pingback: Earthworms Are Bad News for North American Forests – Laidback Gardener

  3. Ick! Like a horror movie!

  4. I don’t have them on my property but I know of gardeners an hour and a half from here who do. I have seen advice to wash all the soil off plants that you buy or receive in trade, but I can’t find anyplace that tells you what to do with the water from that washing. Surely if the potting soil had cocoons they would still be viable and the water used to bareroot the plants would contaminate the ground where it was poured. Or am I mistaken about that?

  5. We must prepare ourselves for the upcoming environmental disaster. Thank you 😊

  6. Annie Morse

    That mustard bath just about killed my citronella plant, so I’d be careful where you test for worms.

  7. Linda Dufelmeier

    I have found that the mustard test is ineffective for the effort it involves. When I see an area that I know through experience holds jumping worms, the mustard may bring up 2. If I dig down I may find 6 or more. I have a massive infestation of jumping worms that I believe arrived in my woodland garden in 25 yards of mixed hardwood mulch in July of 2020. Since early August/late July of 2021, I have spent 2-4 hours each day hand picking jumping worms from our 3/4 acres of woodland garden to the extent that friends are concerned about my lack of balance in my life. And many many hours researching this nightmare online. I have “harvested” thousands and thousands and pound after pound of these worms and have honed my technique. I can say that they do not stay on the surface of the soil. They are masters of going about six inches below the soil surface to feed on the network of roots and fungus in the woodland habitat. We have edged our woodland pathways with fallen tree branches that they have devoured in this past season. They will go beneath the surface of the soil to the root ball of established plantings and begin devouring the root ball. I have also found them along the side and underneath large (at this point I have seen 3″ diameter) roots of aged hardwood trees. The descriptions I have read here totally underestimate the jumping worms’ destructive potential. Considering their reproductive ability my focus has been attempting to prevent them from reproducing. At this point, 2022 could be apocalyptic.

  8. Like Linda Dufelmeier I have harvest many pounds in the few days since I discovered them. I am horrified. They are destroying my plantings and lawn. It’s detracted from my stilt grass obsession. I had wondered why my vegetable garden became so unhealthy and why I’d seen no earth worms. My soil is very acidic. My dreams are plagued with these snakelike worms.I have found them in the forest on hardwood roots. They leave the stilt grass and go for what little healthy grass is left. I have 5 acres.. at every root ball at minimum of 20 huge worms. I gave plants away before I realized. I believe they were brought in with mulch. I also think I spread them moving plants in my yard. Very depressing. Ticks,Stilt,Japanese beetles,the worms and Covid.

  9. Me too! I found this page because I’m totally horrified by the infestation I now realize I have. And here I thought I had all this nice tree chips! I’m picking the worms out – not quite by the hundreds, but certainly by the 50s when I take a break. I have to work too. I’ve got a big pail with water and vinegar (everyone local to me says vinegar kills them) that large enough that I can simply toss the ones I find without having to aim closely. My peonies are black. I suspect they’ve eaten the roots? I’m in southern Vermont.

  10. Pingback: Pheretimoid jumping worms confirmed to be in Ontario; can destroy topsoil - Clean North

  11. thoreauvian95

    My property has become overrun with these jumping worms. I was outside all day yesterday and they were in each garden. Everytime I lift a leaf I see one. They are so creepy – it’s like gardening has become an Indiana Jones movie. Like other commenters to this post, I have had many plants either fail to thrive or simply die and also many seeds failed to germinate. In our forest area, we’ve seen the herbaceous layer disappear and garlic mustard move in – which I think is due to these worms. There are way too many to eradicate so I am trying to think about how to adapt my gardening and co-exist with these pests. I am going to experiment with plants that are more vigorous than I would normally plant – like true comfrey, golden ragwort, etc. Maybe we need a support group – these worms really mess with your head!

  12. Marilyn Webb

    My garden is infested too. I take them out by the hundreds and also kill them in vinegar. Then there is the coffee-ground soil above with hidden eggs. Does anyone know if that top layer should be shoveled off and bagged to prevent the spread of the eggs? Can it be turned over to add nutrients below and if I do that will the eggs grow more deeply under the ground ir will they just die? What can I do to kill and get ridbof the eggs after the worms are removed???
    Thanks
    Marilyn Webb

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