Last Updated on April 6, 2022
Have you spotted the dreaded Asian jumping worms in your garden? Here’s what to know about jumping worms vs. earthworms, how to identify jumping worms, and what to do if you find a jumping worm in your garden.
A NEW GARDEN INVASIVE PEST: ASIAN JUMPING WORMS
As though gardeners don’t have enough to contend with, new destructive pests show up in our gardens to add to our frustrations. Japanese beetles in the grapevines, squash vine borers in the zucchini, bunnies chowing the bean plants, SWD fruitflies after the elderberries. Potato beetles chowing precious groundcherry plants.
But jumping worms are another thing altogether. They don’t attack just one crop, they destroy your SOIL. As in the web of life all your plants depend on. Here’s what to know about jumping worms and what to do if you spot them in your garden.
WHAT ARE ASIAN JUMPING WORMS?
Asian jumping worms (Amynthas agrestis) also known as crazy worms, snake worms, wrigglers, or Alabama jumpers, are a type of earthworm known for voracious eating habits and speedy spread, leading to severe degradation of topsoils as they consume all the organic matter.
Documented in North America at least since the 1930s (some sources say as early as the mid-nineteenth century), Asian jumping worms have now been identified in half of the states in the US as well as at least one Canadian province. Many areas have found them for the first time in the last few years.
More than one species appears to be invading North America. In addition to Amynthas agrestis, researchers report a co-invasion of closely-related Amynthas tokioensis and Metaphire hilgendorfi.
ASIAN JUMPING WORMS VS EARTHWORMS: WHY ARE ASIAN JUMPING WORMS A PROBLEM?
While earthworms aerate the soil and enrich it with their excrement, Asian jumping worms eat organic matter so quickly, it doesn’t have time to break down. Unlike the helpful earthworm castings that feed our garden plants, the castings of jumping worms seem to keep nutrients bound up and can easily get washed away, depleting the soil.
According to the UMN Jumping Worms Project, the jumping worm “radically alters soil structure and chemistry.” Jumping worms consume the organic matter in the upper layers of topsoil, leaving soil without the ability to hold moisture or deliver nutrients to plants. They also loosen the top layer of soil so much, plants’ roots have a hard time hanging on and obtaining the nutrients they need. Researchers in forested areas have described the effect around trees as though the trees have gingivitis, and the soil begins pulling away from tree roots.
As an invasive species, they also appear to displace European earthworms, which though also a non-native species that’s become prevalent over the centuries, don’t destroy habitats in the same way jumping worms do.
Researchers think jumping worm populations may be growing more quickly than in previous decades, and they don’t know yet why they’re spreading more rapidly.
While jumping worms are a concern for gardeners, researchers are more worried about their effects on forest ecosystems.
Jumping worms reproduce parthenogenically (without mating), making them even more effective at increasing their numbers. One worm can create an infestation all by itself, so introducing a single worm to an area can eventually destroy its soil. Jumping worms reach maturity twice as quickly as European earthworms, so they can have twice as many generations per season.
Jumping worms have unfortunately been sold as bait and as compost worms, helping to spread them further.
Interestingly, North America didn’t have earthworms before European settlers inadvertently brought them over in the 1600s.
ASIAN JUMPING WORM IDENTIFICATION
I was surprised how few of my seeds germinated this season, but I figured I hadn’t managed to keep the soil moist enough in the insane swings in temperature (25 one day, 68 another) we had in early spring.
It turns out soil infested with jumping worms inhibits germination. When I pulled back the straw on a spot in my raised bed that I hoped to replant in early July, I noticed the soil looked different than I’d ever seen it. Garden in one place for awhile, and you know what to expect from your soil. It often has a certain look or feel. My soil had never looked like this before.
The top layer was crumbly and loose on top, the consistency of ground beef. It can also look like coffee grounds, which, as it happens, you don’t want to use directly in the garden anyway, so there’s no chance of mistaking grounds for worm-ravaged soil. Here’s what to know about using coffee grounds in the garden, and here are safer uses for used coffee grounds.
Then I spotted a worm that wriggled away far more quickly than the European earthworms I’m accustomed to. I grabbed it and spotted the telltale white band (called a clitellum). You can see it clearly in the photo I took below.
This band is even with the rest of the worm’s body and a whitish or grey in color. Earthworms, on the other hand, have clitella close in color to their body, which rises above the surface of their body and does not form a complete ring (usually described as saddle-shaped). European earthworms also move more lethargically compared to the vigorous wiggling action of “crazy worms.”
Other worms I found as I dug around in the soil were also fast-moving, but not all had the signature white band. I suspect these are immature. I’m waiting for the jumping worm experts to get back to me on that issue.
Keep this printable factsheet from the University of Wisconsin handy to help you identify Asian jumping worms.
Here’s a helpful overview and video of jumping worms doing their “crazy” movements to help you identify them from the Minnesota DNR.
HOW TO GET RID OF ASIAN JUMPING WORMS: NO ONE KNOWS YET
Unfortunately, there isn’t an easy solution to getting rid of jumping worms once you find them in your garden. Sorry I can’t point you to an easy remedy for this problem! The University of Minnesota Extension advises, “there are no recommended control measures at this time beyond hand removal and disposal in the trash.”
But university extension services are asking gardeners to try different jumping worm control methods and report back about their findings.
PREVENTING JUMPING WORMS FROM COMING INTO YOUR GARDEN
Preventing jumping worms from getting in your garden in the first place is your best bet, but it’s not entirely practical. The barely-visible cocoons of jumping worms can hitch a ride on mulch, compost, or even plants you got from a nursery, likely how they wound up in my raised beds.
One source I found recommended checking potted plants you purchase. Remove it from the pot and look at the roots. Jumping worms may consume the roots, so that would be one tip-off, though not a certain one if you have few or immature jumping worms. Pouring a mustard solution (see management strategies below) can help drive them out.
If you can find mulch and compost that has been heated above 104 degrees to manage pathogens, you’re less likely to bring unwanted pests like jumping worms into your garden.
Though you likely won’t be able to spot tiny cocoons hiding in every bit of mulch and soil, if you’re on the lookout for jumping worms and they’re mature enough to identify, you can take steps to avoid bringing them into your garden.
Check the mulch, potting soil, compost, and any potted plants you bring home for worms. If you identify jumping worms, immediately bag up the material and dispose of it. You don’t want to put any of it in your garden,
Alert the source of material to the problem so they can stop selling it and potentially spread jumping worms further.
You may also bring tiny cocoons into your yard on shoes or equipment, so take care to remove soil from shoes if you’ve gone hiking and keep your equipment in your own yard. If you share equipment like shovels, be sure to clean them before using them at a different property.
WHAT TO DO IF YOU SEE A JUMPING WORM
1. Positively identify jumping worms
If you spot an Asian jumping worm in your soil, grab it and put it in a container. Rinse off any soil and take a photo and a video to get a positive ID from your local extension service.
2. Store samples
Keep the worm in a container in your refrigerator in case researchers would like the sample.
3. Gather all you can
Take a plastic bag out to the garden and grab all the worms you can find. Seal the bag and put it in the trash. Some sources suggest allowing the bag to sit in the sun to kill the worms first.
4. Do NOT share soil or plants
Gardeners love to share plants (a favorite way to get plants free), but if your garden has Asian jumping worms, you do NOT want to share them. Don’t move any soil or plant material from your garden once you find jumping worms.
5. Experiment with management techniques
There are a number of control methods home gardeners are experimenting with.
Read more about the methods to get rid of jumping worms in the section below.
ASIAN JUMPING WORM CONTROL METHODS TO TRY
The good news for home gardeners is that since we’re working in limited spaces, we have a chance to control the populations of Asian jumping worms. Jumping worms stay in the top couple inches of soil and they loosen it as they go about their destructive paths, so finding and grabbing them is relatively easy. Not so much if you’re dealing with a whole infested forest.
When you spot a jumping worm, grab it and bag it. When you’re done catching worms, seal the bag and leave it in the sun to kill the worms. Then dispose of it in the trash.
2. Mustard Pour
Water mixed with powdered mustard can drive out jumping worms. Note that it won’t kill them, but will force them to the surface, making it easier for you to handpick.
To make a mustard soak: Mix 1/3 cup ground mustard in 1 gallon of water and soak the area to bring the worms to the top of the soil. Collect them in a bag and put it in the trash.
You can use mustard water on purchased potted plants as well. Researchers recommend a mustard pour as a way to check for jumping worms in plants you bring home from a nursery, though it won’t do anything for the cocoons that may remain in the soil.
Mustard seed powder is very inexpensive, and it may have other uses in the garden, helping to deter other bothersome pests like aphids and potato beetles.
Some gardeners are trying solarizing — heating soil by covering with clear plastic to trap solar heat — to kills jumping worms and cocoons. Experiments have shown that the cocoons of jumping worms can’t survive temperatures above 104 degrees, so if we can heat our soil to that level for a few days, they think, we may kill off the next generation of jumping worms.
I’ll be trying this method on my raised beds at the end of the season, leaving the plastic down so at the beginning of the next season so when we get a warm up, everything can get nice and fried long before I would even think about planting anything.
This interview by Margaret Roach explains more about best solarization practices.
4. Coconut Coir
Some gardeners are finding that mulching with coconut coir may inhibit Asian jumping worms. Sold in big bricks you hydrate and spread in the garden, coconut coir is also considered a more eco-friendly alternative to peat moss.
You can find coconut coir mulch in many garden centers, or buy it online hereor here.
One researcher I contacted told me that he’d “heard anecdotally from gardeners that jumping worms don’t mind coconut coir,” so let us know what you find.
Some gardeners experimented with adding used tea leaves to the garden throughout the growing season and reported a reduction in population. Tea leaves are one of many plant sources of saponins (see more below), which may be why they help with Asian jumping worms. Tea seed meal gets mentioned in the resources on jumping worms as well.
You can save tea leaves (and ask friends to as well) and add them to your garden throughout the season. Brewing tea from loose tea leaves will also save money and cut waste from tea bags.
Saponins are compounds that plants use as natural pest-deterrents that foam when agitated in water, creating a soapy substance that accounts for their name (sapo is Latin for soap). They’re the bitter compound we rinse off before preparing quinoa, and they’re what make soap nuts a useful zero waste detergent.
I’m waiting to hear back from folks at the Jumping Worm Project, but I’m wondering if other readily-available sources of saponins might be helpful to try as well. Easy-to-find horse chestnuts are rich in saponins (and sometimes used to make foraged laundry detergent), as is soapwort root, soap plant, buffalo berry, English ivy, and oats. I’m interested in trying to mulch my garden with some of these plants to see if they bring down the jumping worm population.
I contacted one of the leading researchers on Asian jumping worms, Brad Herrick, and he reported that “In our small trials with Early Bird (saponin based fertilizer), we found that it was extremely effective at killing jumping worms, but direct contact was needed. We delivered the pricier using a backpack sprayer and really drenched the soil.”
Early Bird fertilizer, a 3-0-1 fertilizer made from tea seed meal that had long been used by golf courses for controlling earthworms, is no longer manufactured, unfortunately.
Herrick advised that if gardeners wanted to try using saponin-rich plants, that “applying them as slurry or some way that would breakdown quickly with irrigation is key. The chemical needs to get into the soil.”
I sincerely hope you don’t spot jumping worms in your garden, but if you do, please leave a comment and share what jumping worm control methods you try and how they work.
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Susannah is a proud garden geek and energy nerd who loves healthy food and natural remedies. Her work has appeared in Mother Earth Living, Ensia, Northern Gardener, Sierra, and on numerous websites. Her first book, Everything Elderberry, released in September 2020 and has been a #1 new release in holistic medicine, naturopathy, herb gardening, and other categories. Find out more and grab your copy here.