Invasive Jumping Worm Frequently Asked Questions

The following FAQ was developed from discussion at UMass Extension's January 2022 Jumping Worm Conference. Questions have been edited for clarity.

Identification

Is the clitellum (band of contrasting color close to the head) on a jumping worm raised or swollen?
The clitellum should be more or less flush with the rest of the body. However, when jumping worms form cocoons the clitellum may appear swollen. An important feature for separating jumping worms from European earthworms is the fact that, in jumping worms, the clitellum wraps entirely around the worm. In other species, it does not wrap completely around the earthworm, giving it the appearance of a “saddle”.
How much magnification is needed to identify the bristles (“setae”) on segments of a jumping worm’s body?
Magnification of 5 to 10 times, such as that found in a hand lens, should be sufficient. The challenge is keeping the worm still long enough to see the bristles.

Biology

How deep in the ground do jumping worms live?
Jumping worms are known as epi-endogeic earthworms, that is, they live at or close to the surface. Most years and under normal conditions, they do not burrow deeper than 4 inches. However, this is dependent on soil type and duration of invasion. Adults and eggs can be found deeper than 1 foot in some circumstances. Anecdotally, researchers using bokashi (a fermented compost buried at about 2 or 3 feet) on potatoes found jumping worms at that depth in the fermented food waste when digging up the potatoes.
Are jumping worms seen during the day when gardeners are out planting and weeding rather than 'regular' worms which might be seen at night?
Yes, jumping worms are seen and very active in the daytime.
Can adult jumping worms survive the winter in warmer climates (like North or South Carolina)?
Even as far south as North or South Carolina or outwest in California, the species of jumping worms in the U.S. are annual worms. However, they may live a little longer in warmer climates and thus produce more cocoons.
Might new worms be seen hatching in late summer and early fall and how long will the worms survive?
Jumping worm (Amynthas spp. and Metaphire spp.) eggs can hatch year-round, when soil temperatures allow for it. Most adults die during frost. Even during ideal rearing and feeding conditions, adults do not live more than 1.5 years.
Can the different species of jumping worm interbreed? Are there hybrids?
Jumping worms are regarded as parthenogenetic (i.e., they reproduce without fertilization by sperm; asexual). A single individual can produce viable eggs that will hatch into juveniles. Without sexual reproduction, it would be highly unlikely that the different species could hybridize. Our current understanding is that these earthworms reproduce asexually, however the question about whether or not sexual reproduction may be possible for some or all of these species may not be (currently) fully understood.
Do jumping worms reproduce differently than other earthworms?
While all earthworms hatch from cocoons, jumping worms are unlike most other kinds of earthworms in that they self-fertilize and do not need mates to reproduce.
What is the purpose of the clitellum, the light-colored ring around the jumping worm’s body?
The clitellum forms a gelatinous sheath into which eggs are deposited. That sheath then moves forward and is sloughed off as a cocoon as it travels over the worm’s anterior.
What is the longevity of jumping worm cocoons? Will they survive for multiple years?
Yes, cocoons can survive for multiple years.
Will jumping worm cocoons still survive if they are placed in a trash bag and thrown away?
It is possible, although that depends on what happens to the trash bag and its contents. For example, if the bag were heated to temperatures at or above 104°F for 3 or more days, the cocoons would not survive.
Do jumping worms shed the end of their tail when threatened?
Sometimes, not always, and not all of them at the same rate. This adaptation is a way of avoiding predators. Other organisms have this adaptation, so various worm species other than jumping worms are likely to shed their tail as well.

Abiotic Conditions & Jumping Worms

At what temperature will mature jumping worms and cocoons die?
Worms will likely die at a temperature of around 88 °F (30 °C) in a dry soil. The more moisture in the soil the more heat the worms can tolerate. An upper temperature limit for cocoons and juvenile and adult earthworms is about 104 °F.
If jumping worms don’t survive freezing temperatures, why doesn't cold weather kill their eggs?
Unfortunately, temperatures do not get cold enough to kill eggs which are insulated in cold- and drought-resistant cocoons.
How cold does it need to be to freeze/kill the cocoons, so they don't hatch in the spring?
At one study site in Vermont, cocoons survived -12°F. Scandinavian researchers found that cocoons survived -40 °F, the coldest temperatures tested. And a fraction of the cocoons may survive to lower temperatures.
Can established jumping worm populations move uphill significantly? Or is most of their natural spread facilitated by gravity/water?
Jumping worms utilize gravity to help them disperse, but it does not stop them from expanding uphill under their own locomotion or with human activity.
How might jumping worms respond to fire, especially since fires are usually suppressed on local preserves?
Soil is a remarkable insulator, so even 2 inches (5 cm) below the surface, the heat of a fire is greatly diminished. Worms can burrow away from a fire.

Impacts of Jumping Worms on Soil

What are castings?
Also known as frass, castings are basically earthworm poop, a combination of organic matter and soil minerals, depending on the earthworm’s diet.
Are the castings of jumping worms nutrient rich like the castings of night crawlers and red wigglers?
Yes, jumping worm castings are also nutrient rich. However, jumping worms should not be used in vermicomposting as it has the high potential to spread their eggs.
What is the impact of jumping worms on leaching in soil?
Leaching is a technical term used to describe the movement of nutrients and dissolved organic matter with water, generally vertically downward, i.e., toward ground water. Leaching of nitrate, phosphorus, and other chemicals can pollute groundwater. Earthworms in general produce castings that are enriched in nutrients and more than one paper has reported that the presence of earthworms can increase nutrient leaching. (See Domínguez, J., Bohlen, P.J. and Parmelee, R.W., 2004. Earthworms increase nitrogen leaching to greater soil depths in row crop agroecosystems. Ecosystems, 7(6), pp.672-685, and Costello, D.M. and Lamberti, G.A., 2008. Non-native earthworms in riparian soils increase nitrogen flux into adjacent aquatic ecosystems. Oecologia, 158(3), pp.499-510.)
Are mycorrhizal fungi affected by jumping worms and have there been any studies on earthworm impact on mycorrhizal fungi in forests?
A few studies have been carried out. They suggest the beneficial association between mycorrhizal fungi and plant roots gets interrupted by the soil disturbance (“bioturbation”) invasive earthworms cause.
In areas where crumbly soil and few leaves are found, have jumping worms already moved out?
Not necessarily, since worms persist in areas they’ve colonized. Depending on the time of year an area is examined, e.g. November to May, it may appear worm-free because the adults are dead or have retreated to a moist refuge, but cocoons are present in the soil.
Are jumping worms less likely in a raised bed since they are surface feeders?
Unfortunately, a raised bed is not less likely to have jumping worms, since the worms will thrive near the bed’s soil surface and can enter gaps between wood during wet periods. Warmer spring soil temperatures in raised beds may even hasten the worms’ development.
Can infested garden soil be used next year?
Yes, jumping worm infested soil can still support crop growth, with a few potential caveats. Some shallow rooted plants may not do as well as those with deeper root systems. And direct-sown plants may not germinate or establish as well as planting out reasonably large transplants. Larger transplants’ roots will sit below the layer of the worms’ crumbly castings. However, more research is needed to determine which plants and practices may be impacted by the worms.
Is adding compost to jumping worm infested soil of any value?
Yes. While adding compost feeds earthworms, it also improves the soil in that location.

Ecological Impacts of Jumping Worms

Are there noticeable differences in an ecosystem with jumping worms compared to those without (e.g., reduced litter, reduced understory diversity)?
There are two diagnostics to identify sites with jumping worms. First, look for a bare forest floor with little to no understory. Then, check for the characteristic coffee-ground-like castings. The second step is necessary because there are also other earthworms that cause a denuded forest understory.
Are jumping worms killing forests?
They are changing the nature of the forest. For instance, they are reducing the regeneration of seedlings that require forest floor germination, such as maple. This is particularly damaging to native tree and understory plant populations, and is exacerbated in the presence of high deer browse pressure.
How long does it take a forest floor to rehabilitate itself after a jumping worm disturbance?
Currently, the answer to that question is unknown, but it is acknowledged that in soils where residential land uses have been abandoned, it would take 100-200 years to build up the same amount of organic matter as that found in the forest.
Is it true that jumping worms don't preferentially eat oak leaves?
They will generally eat nearly all types of dead leaves. It simply depends on whether they have other, more or less palatable foods present. Jumping worms can eat wood if it is advanced enough in decomposition.
Are certain plants/root structures more or less susceptible to soil conditions created by jumping worms?
Information currently available suggests that rooting is difficult, drought symptoms may appear in infested containers, and seed germination may not be as successful as it might be without the worms.
How do woodland wildflowers, such as trillium, survive in jumping worm infested soil? Does an annual application of aged, fungal-rich wood chips benefit the plants?
Research is limited, and impacts on species including Trillium depend upon the presence of other stressors such as deer browse pressure. There are woodland plants/wildflowers (e.g., trout lily, ferns, jack-in-the-pulpit), primarily those that have below ground reproductive structures like stolons, that don’t necessarily rely on a seed bank to establish. Plants such as groundcovers and vines that can root in disturbed soils can still proliferate in the presence of jumping worms. In worm infested soils, these types of plants might do better than plants spreading mainly via seed. Using wood chip mulch can benefit the plants; at the same time, it is known that jumping worms produce enzymes that can break down wood chips for food (so it might also benefit the jumping worms).
Do jumping worms eat invasive plants?
The greatest damage to plants from earthworms is indirect in that worm consumption of the organic material at the top of the soil reduces the seed bank from which forest plants grow. What is left may be consumed by deer.
What is the relationship (if any) between garlic mustard and jumping worms? Could the worms make the soil more attractive to garlic mustard or vice versa?
Earthworms disturb soils and some invasive plants thrive on disturbed soil. It is possible that jumping worms make it easier for garlic mustard to establish, but garlic mustard does not depend on them. Further research may be necessary to establish a relationship.
What are the recommendations for watershed managers who are managing/stewarding forest lands adjacent to drinking water reservoirs?
Research has just begun so the extent of jumping worms’ impact on drinking water is still hypothetical. Practical suggestions might include (1) be careful about bringing in outside material, e.g. mulch, soil, restoration plantings, (2) pay particular attention to steeply sloping areas, and (3) use signs to discourage dumping of yard waste.
How might the presence of jumping worms impact robin migration?
Jumping worms are very small when birds migrate. The worms tend to be active from mid-May to November, and are not likely to be much of a food resource for birds during migration. However ground-foraging birds like thrushes, including robins, commonly consume earthworms present at the soil surface.

Distribution, Accidental Movement, & Natural Dispersal

How did the jumping worms get here? Is there any effort to stop their import?
The first jumping worms were reported in California in 1860, i.e., shortly after Commodore Matthew Perry forced the opening of Japan to trade. Anecdotally, the cherry blossom trees in the Washington, D.C. area have been linked to their import to the eastern U.S. Most jumping worms move around with horticultural practices and products. Phytosanitation has reduced the number of them coming in at this point.
How might jumping worms have been introduced to wooded, un-landscaped areas?
It’s possible the worms and cocoons have spread to these areas with human help, through activities such as fishing and hiking. Additionally, they are capable of dispersing on their own.
Why does it seem that gardeners who have been gardening for decades have only been spotting jumping worms in the past couple of years?
It’s not clear, since the worms have been around in Massachusetts and New York for quite a while. It may be that during the past few years, more people were gardening and purchasing quantities of compost and plants potentially containing worms or cocoons. However, that is merely a hypothesis about the impact of COVID on gardening and worms.
Why do the jumping worm genera Metaphire spp. and Amynthas spp. tend to co-occur? Are there many cases where the genera or individual species occur alone?
Perhaps these genera co-occur because they are most adapted to the climate or type of leaf litter present. The genera can and do occur by themselves. However, they can survive together and, in many cases, they are introduced together inadvertently.
Are jumping worms less prevalent in turf (especially low-cut turf, such as on golf courses) since they seem to dwell more where there is a cover of leaf litter or mulch?
Some turf areas have thatch (a layer of living and dead stems, leaves, and roots at the soil surface) that can be very attractive as a food source for jumping worms. There are enough earthworms of various species on golf courses to be a problem.

Bioaccumulation of Heavy Metals

Is it true that jumping worms bioaccumulate toxins from the soil and therefore are not good to feed to chickens?
In terms of bioaccumulation, jumping worms can be harmful if your soil has elevated concentrations of metals (e.g., lead, mercury, arsenic) or even organic compounds (e.g., banned pesticides like DDT, polychlorinated biphenyls). Low levels of metals, metalloids, and other contaminants in the soil ensures low transfer to chickens and other ground foraging birds. In general, it is not recommended to feed jumping worm species to chickens, especially if the eggs or meat from those birds is to be consumed.

Climate Change & Jumping Worms

Is it likely that the increased population of jumping worms in New England is related to warming temperatures?
1. It is possible that climate change is promoting population increase and expanded distribution of jumping worms. The growing season has increased by several days, primarily in the spring when the cocoons hatch. A longer season means that the worms may have more time to produce cocoons. More importantly, in areas where they are at the margins of their range, they get a few more days to become reproductively mature. Jumping worms need approximately 80 to 90 days to mature. So, a location that had a 79-day frost free period 20 years ago would likely be a place where jumping worms could survive now because they’re able to produce cocoons. There are now reports from Canada where worms had not been reported previously, possibly indicating a spread in territory or the presence of larger (and therefore noticeable) populations.

Mulch, Soil, Compost, & Plant Sales

How will a consumer know if mulch or soil sold by a company is jumping worm-free?
There is no labeling system in place for this, but it is good practice to purchase mulch heated to appropriate temperatures and duration (104°F for 3 or more days) following protocols that reduce pathogens.
Does “hot” compost kill jumping worm adults and/or cocoons?
Generally, both worms and cocoons die at temperatures above 104°F. However, a windrow and a home compost pile do not have a uniform temperature throughout. Worms can move from areas of high to low temperatures in a windrow. The outside of the compost pile is at ambient temperature and even a few inches in, temperatures can be tolerated by the worms.
Can soil amendments stored on the ground be reinfested with jumping worms?
Yes, take precautions to store materials away from contact with worm-infested areas.
After confirming the presence of adult jumping worms in the garden in September, what can a gardener do to reduce the population as worms begin to hatch from cocoons the following spring?
There are currently no effective means for managing worm populations, although research is ongoing. The best approach is to try to avoid accidentally introducing worms to uninfested areas via plants, tools, soil, compost, and mulch.
How can gardeners safely share plants with friends or provide plants for garden club/community plant sales?
One way to address the risk of spreading jumping worms with plant material is to share bare root plants. Clean soil from plants in a basin of water and inspect the roots to ensure no soil remains. Afterwards, strain the wash water and discard any solids larger than a mustard seed in a trash bag. Seal the bag and place it in the sun before disposing. This can also be done by consumers after purchasing potted plants.
Have any efforts been made to control the sale of jumping worms for fishing and composting activities?
Jumping worms are not good composting worms and should not be used as such. The worms are available for purchase on the Internet, although purveyors acknowledge that they may be a problem. A few states have regulations that won’t allow Internet purchases and transport across state lines. New England states do not have those restrictions yet, as of the publication of this document.

Biological Control and Chemical Management

How are jumping worms dealt with in their countries of origin?
Jumping worms do not appear to be a problem in their native locales. The reasons are not entirely clear, but possibilities include the quality of forest floor leaf litter, competition from similar worms, and predation.
Do earthworms have any predators here?
Yes, they do. Birds, salamanders, and snakes all catch worms. Terrestrial flatworms (planarians) are earthworm predators; they contain a nerve toxin, tetrodotoxin (TTX), which kills worms and has been described as a potential environmental hazard. However, flatworms are also exotic and can become invasive.
Will birds eat the jumping worms?
Birds eat the worms but probably not at a fast enough rate to control the population.
What are the risks/benefits of using chickens to remove jumping worms?
Earthworms are bioaccumulators of toxic substances (such as heavy metals) and should not be fed to chickens, especially those to be used for egg or meat production.
Is using Beauveria bassiana, an entomopathogenic (pathogenic to insects) fungus, effective at managing jumping worms?
B. bassiana occurs naturally in the soil as do other entomopathogenic fungi like Metarhizium spp. and Isaria spp. There are different strains of these fungi and not all strains may be virulent enough. It is also unlikely that the populations found in nature are big enough to infect the worms. Research is ongoing.
What is the status of using tea seed meal for controlling jumping worms?
Tea seed meal is labeled for use as a lawn fertilizer only and is not legally approved for any other use. It contains naturally occurring saponins (chemicals with soap-like properties), which have been found to kill earthworms. However, it is not a certified vermicide and its effects on other organisms, particularly mollusks and fish (if it gets washed into waterways), can be severe.
Is there evidence that jumping worms avoid plants that produce a large amount of saponins?
There has not been any research on that to date.
Can alfalfa, with its high saponin content, be used as a vermicide?
Anecdotally, alfalfa has been suggested as a potential jumping worm treatment, but controlled studies using alfalfa meal and pellets have not been effective.
Would manipulating the biology of jumping worms, e.g., sterilization, prevent them from multiplying?
Because they are not sexually reproducing, it would be difficult to release genetically modified males to reduce the reproduction rate (as is done with mosquitos). Some newer substances based on RNA have been developed that disrupt an organism’s growth. These products exist for a very small number of organisms that have a huge impact on economic crops (e.g., Colorado potato beetle).
What is a mustard extraction mix used for and how is it prepared?
While it is not considered an effective control method, a mixture of mustard and water poured slowly over the ground irritates worms in the soil and will bring them to the surface. (It will not kill worms.) Worms can then be collected for identification purposes and counted to get a rough idea of the level of infestation. The recommended mixture is 1/3 cup of ground yellow mustard seed in 1 gallon of water.
What effect does mustard have on plants and other soil fauna?
Mustard can be used safely around most plants, and is an expellant of organisms in addition to worms. After collecting worms, flush the mustard mixture in to the soil with plenty of water.
Is it best to put down mustard solution to bring the worms out of the ground before they deposit cocoons?
Not necessarily. Mustard extraction isn’t a control technique; it will inevitably miss some worms, particularly deeper ones or ones that slink away at the surface unnoticed.

Physical Management

Would tilling the soil kill jumping worms?
Many of them, yes. A good time to till is in May before the worms turn into adults and after a lot of them have hatched.
Would a blow torch on an open area of soil kill the jumping worms and or castings?
It may kill some of them, but not all of them since some of them would be underground and protected from bursts of heat. Prolonged heat exposure of the soil surface would probably allow enough heating of lower soil layers to kill the worms. However, using a blow torch is not advised.
Will dropping jumping worms into a bucket of soapy water kill them?

Yes. If juvenile or adult jumping worms are found in a garden or landscape, dropping them into a bucket of soapy water will kill them. However, doing so as a management technique may not be entirely effective. While you may eliminate as many individuals as you can find in an area, it is highly likely that there will be cocoons and eggs left behind. So this practice will not eradicate all jumping worms from a single location, and it is currently unknown whether this will reduce populations to any significant degree.

Jumping Worms, European Earthworms, Native Earthworms

How do jumping worms differ from European earthworms?
One of the most prominent differences between them is the appearance of the clitellum. The clitellum of a jumping worm is distinctly white or much lighter than the color of the rest of the body, and is annular--completely encircles the worm’s body. The clitellum of non-jumping worms is somewhat similar to the color of the body, and assumes more of a saddle shape--very distinct on the upper side of the body and flattened on the underside.
What is the difference between the cocoons from jumping worms and European earthworms?
If the cocoon is elongated then it is most likely not a jumping worm cocoon. Jumping worm cocoons are very spherical. (Bear in mind some European worms may also have spherical cocoons!) Cocoons are tiny and difficult to see.
Do European earthworms cause harm in farm soils?
It’s possible and complicated. For instance, night crawlers make very deep burrows that bypass the root zone. These burrows can take agrochemicals (fertilizers and pesticides) to lower depths without encountering the rich soil at the soil surface or the plant roots. As a result, less fertilizer is taken up by the plants. The loss of the fertilizer from the field means that nutrients either end up in groundwater, or if there is a drainage system, it can end up in surface water. In either case, nutrients end up in the wrong place and can cause environmental harm, such as eutrophication of ponds and streams (algal blooms).
Are there any native earthworms in New England?
There are very few native earthworms in New England due to glaciation. Over 99% of earthworms in the region are European or Asiatic.

Reporting Jumping Worms

Where should citizens report jumping worm sightings?
There is no single location collecting jumping worm reports in Massachusetts, as they are widespread throughout the state. However, worms can be reported to EDDMapS (https://www.eddmaps.org/), which will map the reports and maintain publicly available information. This is the reporting page recommended by the MA Department of Agricultural Resources for jumping worm reports coming from Massachusetts. Other states may also consider reporting to EDDMapS, or either of the following additional options: iMapInvasives (https://www.imapinvasives.org/) or iNaturalist (https://www.inaturalist.org/). Finally, other state departments of agriculture may be collecting these reports; however, the MA Department of Agricultural Resources is not at this time.

Management Research

What is solarization and is it effective for eradicating jumping worms and cocoons? How does it work?
Solarization is the process of using the sun to heat soil, compost, and/or mulch to a temperature of at least 104°F for approximately 3 or more days, above which worms and cocoons cannot survive. The process appears promising, although methodology is still in the research stage, as investigators examine factors such as appropriate covering and underlay (e.g., translucent plastic), maximum dimensions of amendment/soil batch, and length of time.
What is the latest research on using biochar to manage jumping worms?
There is little in the literature regarding biochar research vis-a-vis jumping worm control. A small experiment showed some effectiveness of biochar when soil moisture was kept at low levels. The two stresses together probably killed the worms. Size and sharpness of biochar particles is likely to be important, since the mode of action might be disruption of the worm’s gut lining. Particles that are too small won’t have an effect, and those that are too large would not be ingested. Worms have a crop containing relatively large grains that help grind ingested materials to make them more palatable. It is possible that those grains grind down the sharp edges of biochar. In short, more research is needed.
What is the latest research on using sand to manage jumping worms?
Similar to biochar, the size and angularity of sand particles would be important. Further research is needed.
What is the latest research on using diatomaceous earth to manage jumping worms?
Anecdotal evidence suggests that diatomaceous earth is not effective in controlling worms, possibly due to the small size of the diatom shells. There does not appear to be any large-scale research on using diatomaceous earth at present.

Credits

Contributing Authors:

Dr. Annise Dobson, Postdoctoral Researcher, Yale School of the Environment
Dr. Josef Görres, Dept. of Plant and Soil Science, University of Vermont
Dr. Justin Richardson, Dept. of Geosciences, University of Massachusetts, Amherst
Dr. Olga Kostromytska, Extension Assistant Professor and Turf Entomologist, UMass Stockbridge School of Agriculture
Tawny Simisky, Entomologist, UMass Extension, Landscape, Nursery and Urban Forestry Program

Editor:

Jennifer Kujawski, Horticulturist

Last Updated:

July 2022

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