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Jumping worm. Photo: Joe Shoenfeld

Jumping Worms Conference

By any other name Amynthas and Metaphire spp. (also called jumping worms, snake worms, crazy worms) have captured our attention. In late January, 2022, over 700 people tuned into a two-day online University of Massachusetts Extension seminar focused on this invasive species.

Attendees zoomed in from across Massachusetts, the East Coast, 14 additional states, and Canada.  These enthusiastic learners set a new attendance record for Extension seminars. The most frequent questions from frustrated property owners concerned how to get rid of them. “Not easily,” attendees were told, but the real answer lies in how to learn to live with them and minimize the risk of dispersing them long distances.
These invasive wiggly earthworms – very different from our beneficial native earthworms – are multiplying in home and commercial gardens, mulch, soil, compost piles, and forests.  In any other setting, this story might read like sci-fi invasion movie, but, sadly, it is a boots-on-the-ground true tale as these creepy crawlers invade our gardens, lawns, and forests. But there are steps that can be taken to reduce their spread and population, at least temporarily.  

Experts from the University of Massachusetts, the University of Vermont, and the Yale School of the Environment presented slides and facts on these invasive earthworms, shared up-to-date research that included the history of how they came to arrive in the U.S., their life cycles, and what can be done if they’ve arrived on your property.

What is the Real Problem?

Jumping worms (Amynthas and Metaphire spp.), a group of species originally from Asia, alter soil qualities and make it inhospitable for some plants to thrive. They do this by consuming the upper organic and mineral layers of soil, which can lead to nutrient leaching and soil erosion. This makes it difficult for many native plants and row crops to grow, and some of the most significant impacts of these earthworms have been seen in forest ecosystems.  Once established, they can reach high densities and alter soils and affect understory plants.

UMass Speakers

Olga Kostromytska, UMass extension assistant professor, presented a vast array of information on the earthworms in managed and urban landscapes, specifically in turf. In what is becoming common information, she found that all adults die off in the winter, but leave their resilient, egg-containing cocoons (as small as a mustard seed) behind to give rise to the population the following year. She emphasized the fact that no chemicals are currently labeled for earthworm control.  While she presented information about toxicity and behavior effects of products containing saponins and other materials commonly used in turfgrass, these products should be used only as specified on the label. Currently, earthworm population management (including invasive species) is limited to cultural practices, and reducing the spread. Solarization is one of the most effective strategies to “decontaminate” soil media and mulch from the cocoons and worms. These specific methods and techniques are being investigated.  

Justin Richardson, UMass assistant professor in Geosciences, shared his research on ecosystem dynamics and changes as a result of jumping worm presence. He described them as big ecosystem engineers. In 2018, he discovered that out of 28 forests in Poughkeepsie NY, they were present in 24 of the locations surveyed. These widespread invasive worms have been discovered on golf courses, forested areas, wooded landscaped areas, home lawns and gardens, and surrounding agricultural fields, just to name a few places they call home.

Richardson offers a few tips to help keep numbers down: keep them out of the forests by avoiding transportation of wood (they can live in and on dead trees and bark); avoid sharing them with others by not transporting mulch or compost (which can contain cocoons filled with eggs) and; identify their signs: if you do not see leaves on the forest floor and observe “pill-like, coffee ground-looking soil,” they are very likely present.  Jumping worms may also contribute, unfortunately, to the loss of native wildflowers including: trillium, lady’s slippers and more. This is because these flowers need nutrient-rich soil, and the loss of leaf litter for seed germination becomes an issue for native flowers to thrive.  

University of Vermont  

Josef Görres, an associate professor at UVM’s Plant and Soil Science Department, presented information on the topic of, “Why Care and What to Do.” He helped attendees identify jumping worms by the band around its neck or clitellum.  In contrast to other earthworms, jumping earthworms have a clitellum that is circular and goes all the way around the body. In earthworms from Eurasia (also non-native, but have been present in New England longer), it is of a saddle shape and lays halfway around it. He pointed out that the invasion of a forest by earthworms kicks off a microcascade of ecological changes beginning with the modification of the forest floor which in turn affects the forest vegetation, the food web, and vertebrate species like birds and salamanders. These local changes may also affect wider processes that affect human health and even water quality. The consumption of leaf litter by jumping worms may reduce Lyme disease prevalence, since ticks prefer to bury in leaf litter. However, the loss of the leaf litter and the organic top soil horizon will likely reduce the seed bank and germination rates. In addition, the organic horizon, also known as the duff layer, is where forest plants root and extract nutrients. Although the earthworm castings that replace the duff layer, may have high nutrient content, plant roots won’t thrive in the castings and the nutrients are not accessible.  

Görres advises that if you have jumping worms in your gardens or woods, “Don’t let the worms shame you.” Dr. Görres’s lab is currently researching the use of reduced risk, biological pesticides to manage jumping worms. Further research is needed.  

Görres advises that regarding use of compost, the organic certification requirement does not mean that the compost is free of worms, so be careful. Organic garden amendments like mulches (cocoa hulls, bark, leaf, straw) serve as food for jumping worms. Some of these will feed the worms if you have them. Importing leaf mulch may even introduce jumping worms into your garden. He advises solarizing these amendments before applying them. Be sure to solarize mulches and compost sandwiched between translucent plastic sheets. The bottom sheet ensures that the worms cannot escape into the soil. The top sheet will cause the pile to heat up.  

Görres indicated that in spite of the far-reaching consequences of invasive earthworms, there is currently little research funding available from federal and state agencies.

Yale School of the Environment

Annise Dobson, Postdoc from the Yale School of the Environment, described the impact of jumping worms on plants. Jumping worms consume the organic matter and leaf litter at the top of the soil profile, modifying soil to a gravely texture prone to erosion. This produces low germination rates, root dissection, and unstable rooting, all of which causes roots to dry out. Dobson’s research has also shown that not all native plants respond similarly to jumping worms. For instance, poison ivy grows well in areas infested with jumping worms. She acknowledges that while it is a hard sell to ask people to grow poison ivy, we can use lessons we learn about plant traits to make planting recommendations for gardeners and landscapers. For example, some ground covers, deep rooted plants, plants with stolons, and some ferns may be better at withstanding the impacts of jumping worms. In addition to poison ivy, plants she has identified that can persist in jumping worm-infested soil include trout lily (Erythronium americanum), jack in the pulpit (Arisaema triphyllum), jumpseed (Antenoron virginianum), Christmas fern (Polystichum acrostichoides) and blue cohosh (Caulophyllum thalictroides). Where possible, planting a deep-rooted prairie garden with pollinator-friendly plants may also be a good option.  

Dobson describes one of the first introductions of jumping worms were those imported to Bronx Zoo in 1948 to feed the platypuses in their new exhibit. In 1980, they began to be identified in natural areas in New York City. By 2012 13% of natural areas reported them and by 2019, that number had risen to 64%. One hypothesis is that during Hurricane Sandy, spread may have occurred with 15,000 downed trees in NYC that were chipped to create mulch, then spread throughout the city.  They can also spread in compost moved from site to site, as well as on tire and boot treads.

So…What is A Person to Do If They Have Jumping Worms?

•    Consider modifying behaviors: be cautious when sharing potted plants. Share bare root plants when possible.
•    Do not buy jumping worms as bait. Do not dispose of unused baits in the environment.
•    Do plant bare root plants, even from potted plants (wash roots, strain and dispose of wash debris carefully).  
•    Shop with local businesses that take steps to prevent the spread of jumping worms.
•    Make your own mulch compost on your property.
•    Learn to recognize signs of jumping worm-modified soil that resembles coffee grounds.
•    Log your observations on your favorite App! Here is a good example:  
•    Manage the things you can, but do not panic about those that you can’t.
•    Cultivate deep-rooted species, ground-covers, plants with stolons, and ferns.
•    Opt for planting older, larger plants rather than small seedlings or provide direct seeding in areas infested with jumping worms.
•    Consider a prairie garden or pollinator garden with generally deeper-rooted plants.
•    If you are removing worms from your garden, toss them into soapy water. Dispose of them in a sealed landfill.
•    Do not feed jumping worms to chickens as the worms may concentrate high levels of toxic metals.

Where Can Readers Get Current Information

These UMass Extension fact sheets answer questions about jumping worm prevention and spread –  as well as the biology and identification of these earthworms.  

Annise Dobson helped to create a practical document including prevention tips: Asian Jumping Worms: Homeowner’s Guide