FAQ

Here are the top ten questions people tend to ask us about jumping worms. If you have a question that we haven’t answered here, ask us.

The best time of year to notice jumping worms is in the late summer into fall. Juvenile and hatchling worms are present in the spring, but are much harder to identify. In a garden, you are most likely to find jumping worms in mulched or wood chipped areas. In forests, they will be under leaf litter and underneath dead wood. In a dry year, they will probably be attracted to irrigated areas that receive regular watering. If worms are heavily present, simply pulling back leaves or mulch and disturbing the soil will often be enough to bring them to the surface. Another way to discover them is to mix 1/3 cup of hot mustard powder into a gallon of water and pour that into a square foot area of soil. That will irritate their mucous membrane skin and draw them to the surface; it will also draw any other earthworms, including European earthworms, but you can identify jumping worms with our guide here.

In nursery settings, by mid to late summer, affected potted plants will often have the characteristic castings present; lifting the plants out and assessing the soil should indicate the presence of worms and castings. The castings will be grainy, with a texture like dry, cooked hamburger or Nerd candies, or very very coarse coffee grounds. It’s a loose, granular type of texture that holds together very poorly, in contrast to soil, which is more cake-like. If the plants are heavily pot-bound and their roots are so dense that the castings are less apparent, you can try lifting the entire plant out of the pot; if there are jumping worms, you might see them embedded into the root/soil matrix, even if the rooting system is so dense that you don’t immediately see castings.

Jumping worms resemble the typical European earthworms, but with a few key differences.

• Their bodies tend to be more ‘aerodynamic’ looking—sleeker and pointier at the ends. 

• Mature jumping worms may be anywhere from 2” to 8” long.

• Their clitellum—the ring of lighter tissue around the body—is white to gray, wraps fully around the body of the worm, and is flush to the rest of its body. (This feature is only visible when the worms reach maturity however, and will not be present on juveniles). 

• Their bodies are relatively firm and may even feel ‘muscular’ or snake-like, compared to softer European worms. 

• When touched or disturbed, jumping worms will thrash violently, sometimes wriggling into the air or out of your hand. They can also detach part of their tails to distract predators. 

• They are often present in large numbers—if you see many earthworms at one time, you are most likely seeing jumping worms. European earthworm populations tend to be much sparser and spread out. 

• If you discover areas of soil that seem oddly grainy, lightweight, and coarse, particularly in forest settings, near leaf litter, or in mulched beds, you may be seeing the casting layer left by jumping worms, indicating the presence of jumping worms nearby.

Jumping worms rely on two vectors for spreading out: Human activity and flowing water.

Most of the time, jumping worms are spread when they are small juveniles or in their cocoons, which are extremely difficult to detect. Jumping worm cocoons are as small as a mustard seed and the same dark brown as soil or compost. They are drought- and cold-resistant, so they can overwinter easily, and hatch just as soon as weather conditions are in their favor. And because worms reproduce asexually, a single worm is able to jump-start an entire new colony. 

Human activity such as plant exchanges and retail sales, and introductions of contaminated materials like compost, mulch, and topsoil, are primary ways that cocoons and worms spread. They can also hitchhike in the treads of machines or hiking boots. Organic wastes from infested yards that make it to municipal composting stations or transfer stations contribute to spread as well. 

Water can also carry earthworms long distances as they can exist in water for a while. Overland flow during big storm events carries the worms and their cocoons into streams The streams then take the jumping worms to new habitats downstream.

Ecosystems are a matter of checks and balances which evolved over thousands of years. However, when an organism from one place moves into a totally new environment, it sometimes leaves those checks and balances behind. Think of Japanese knotweed, kudzu vine, garlic mustard, pythons in the Florida Everglades, and spotted lanternfly in Pennsylvania—these species arrived here and took off, because there was nothing to stop them from growing out of control.

It’s the same for jumping worms. We don’t know yet exactly what keeps them in check in their native east Asia, but we do know that they aren’t nearly as abundant or damaging there as here, but we can make some educated guesses. There are many important differences between East Asia and North America. In Japan, most soils are derived from volcanic parent materials. The soils, plants, and animals there are also used to earthworm. The northern soils of North America evolved without any earthworms after the last ice age, so they have a huge abundance of organic matter for these invasive earthworms to eat, but which our native life can’t live without. Maple forests in particular seem to be vulnerable to the invasion which has been linked to the high calcium and nitrogen contents of its litter.

There are probably also parasites, diseases, predators, or competing earthworms in the worms’ native soils as well that we haven’t found yet. A study that compares all these factors in Japan and in the invaded habitats in North America would help identify the factors that make jumping worms so invasive in North America, and may yield hints on how to manage the worm invasion more effectively. 

Jumping worms most likely arrived sometime in the early to mid 20th century, on imported material from east Asia, so they’ve been here a while. However, unless we’re already looking for them, it takes time for an invasive organism to be noticed. A few factors worked against us for that: 

• Our awareness: Earthworms of every kind have benefitted from the idea that earthworms are always good. For the most part, science didn’t seriously understand earthworms as a destructive force until the end of the 20th century, and that research was all done on European earthworms, which have been here for several hundred years. Jumping worms have still only been here a relatively short time.

• Adaptation: Invasive species like these often find refuge in horticulture or gardens before they become invasive. Horticulture, with its irrigation, fertilizer, and organic mulches, creates excellent conditions for jumping worms to thrive when the climate outside isn’t suitable. Some of the first reports of jumping worms came from greenhouses and gardens. The worms may have bided their time in these artificial microclimates until the conditions outside improved. Then, as climate change warmed up the northern climates and expanded the growing season, it created the right conditions for the worms to “jump” the fences into our woodlands and gardens. Meanwhile, that time interval also allowed them to gain a foothold in horticultural materials, where they are now all but endemic. 

It matters because of the erosion issue and loss of nutrients from the ecosystem that specifically jumping worms cause. This is true even when jumping worms invade ecosystems where the European earthworms are already present. And there are still many ecosystems where any earthworm has yet to invade that we need to protect. That includes most of Canada’s boreal forest, which contain some of the greatest reserves of freshwater in the world, and some of the richest stores of soil carbon. 

Reports of jumping worms in sustainable agriculture are increasing in numbers. Any additional erosion would jeopardize the sustainability of these farms. However, many sustainable agricultural practices are also likely to make soil conditions more favorable to jumping worms. Farms that apply for federal cost share need to show that they have no net loss of soil, that is the erosion does not exceed the natural soil loss. With jumping worms that becomes more difficult.

Absolutely! Many animals eat jumping worms, including the American Woodcock, American robins, hawks, foxes, salamanders, voles, and snakes.

But there are two reasons why this isn’t enough: First, these animals don’t seem to eat jumping worms at enough of a scale to dent the worms’ populations and impacts. 

Second, jumping worms accumulate heavy metals when these toxins are available in large amounts in the soil. This is frequently the case in forests where lead and zinc may have been stored from nearby pollution sources over time. So when a bird or a fox or a salamander eats the jumping worm, it’s acquiring a load of heavy metals. We haven’t demonstrated yet what the end result is on wildlife, but we are concerned that wildlife who eat sufficient numbers of these worms may be affected by poisons, and may even help re-introduce them to our watersheds, affecting us. 

Other earthworms also accumulate heavy metals but they don’t reach the same high abundance as jumping worms.

The Healthy Soil Collaborative focuses on the jumping worm invasion in northern North America. However, these worms have also been reported in South Africa, India, Turkey, parts of Europe, a roof garden in Barcelona, not to mention the Southeastern USA where they are called Alabama or Georgia jumpers. More recently they have been found in the Pacific Northwest and in the Canadian provinces of New Brunswick, Quebec, Nova Scotia, and Ontario. The invasion in Canada is very recent and is probably enabled by warmer temperatures and longer frost-free periods that have developed over the past decade.

Almost all of the research on jumping worms has occurred in the US northeast, upper midwest, and southern Canada. We don’t really know what happens when these worms appear in these other ecosystems around the world. So far in the southeastern US, where some native earthworms do exist, jumping worms aren’t yet proving to be as destructive, but they are still creating visible soil changes. Very little data has been published on this however, and it’s an important question that we hope to answer. 

Jumping worms have not yet been reported from subarctic ecosystems in Canada, Europe or Asia. Other earthworms have invaded there however and are modifying soils with measurable impacts on CO2 emissions. A map of suitable climates for jumping worms in North America shows that they can survive as far north as Labrador and within a few hundred kilometers from Hudson Bay. 

Earthworms penetrating the boreal forest and tundra of the world can have devastating consequences for climate change because the worms would accelerate the decomposition of the vast stores of carbon stored in boreal soils.

Right now, there are no products labeled for jumping worm management, so what we describe is only allowed in research. We recommend that products be used for their labeled purpose. Currently, we are exploring off-the-shelf compounds like saponins, found in things like tea seed meal (made from the tea plant), and alfalfa meal, which appear to kill jumping worms by affecting the mucous on their skin. Saponins should never be used around water bodies or wetlands, because they can also hurt anything else with mucous-coated skin (e.g., fish, frogs, salamanders).

We’ve also discovered some promising leads in entomopathogenic fungi, which seem to be somewhat effective at knocking back jumping worm activity. We’re exploring that right now to try to identify the best way to deploy and culture these microbes, and assess off-target impacts. Meanwhile, we’re still searching for more compounds that might even be more effective. Down the line, we anticipate exploring genetically based interventions that may be targeted directly at the worms.

In the meantime, there are many other practices you can use. We provide guidelines to some control methods in our Resources section to things that can be effective, such as heat, solarizing, using alternative types of mulch, maybe trying different kinds of plants. These kinds of interventions have emerged both from our scientists and by community scientists who try things and share their successes and failures with us. We really encourage you to reach out to us and engage with us—we have studies underway right now that rely on individuals just like you for collaborative observation and experimental work. 

We know this is hard. Many of us in the Healthy Soil Collaborative have been where you are. You’re not alone. If you are open to engaging with us, by donating or doing community science in your yard—or both—you can actively help us get that much closer to a viable solution.

The large science agencies in the United States are the National Science Foundation, the National Institute of Food and Agriculture (NIFA), and the National Institute of Health. The availability and direction of funding they give out depends on programs authorized by our government. This process makes these agencies less nimble to react to urgent research needs.

These large agencies also rely on peer review to evaluate proposals from scientists. Peer review is probably the best way to make decisions on funding—but it is also flawed in that proposals are viewed through the perspective of what the reviewers consider important. Many agricultural or soil scientists are simply not familiar with the idea of earthworms as pests and don’t see the relevance of invasive earthworm research. In this evaluation system, many research areas become orphan research. 

The National Science Foundation’s Directorate of Biology is a lot more independent in how they spend their funds. They seek proposals that are very novel, and propose research that advances biological science through the lens of evolutionary or ecological theory. There are good reasons for this because in the long run, advances in knowledge require new theory. This unfortunately means that proposals with a strong applied component and significant basic science, like the research we need to do, are not competitive at NSF.

Finally, government agencies deal with a large number of problems (forest fire, flooding, food production) and so they get many proposals, all of which have at least some merit. For NIFA the success rate is between 10% and 30% for competitive programs. For the NIFA Pest and Beneficials program that would be the most likely to fund invasive earthworm research, the funding rate was 14% in 2020. We’re still fighting a very uphill battle in that in most places, earthworms = good. Invasive earthworms are not yet recognized agricultural pests. 

In short: Funding from the science agencies is scarce and depends on many factors. Invasive earthworm research just is not a high priority.

It is part of the mission of the Healthy Soil Collaborative to change this fact by amassing quantitative assessments of the impact these worms make on climate, agricultural, and high-value ecosystem services. But to get there, we need help—and that is why we are asking for support of any and all kinds to help us continue establishing the research base to persuade the people in charge of protecting our resources and natural world.