Amynthas agrestis: The Crazy Snake Worm

Crazy Snake Worm (Amynthas agrestis) in the wood mulch of a horticultural bed at a tree nursery in Vermont.

Figure A. 1 Crazy Snake Worm (Amynthas agrestis) in the wood mulch of a horticultural bed at a tree nursery in Vermont. Checkout the white ring around the worms body. In Amynthas species it stretches all around the  body and it is well off-set from the rest of the body.

The Crazy Snake Worm (Amynthas agrestis, Figure A1) is an aggressively invasive earthworm that hails from Korea and Japan. Most earthworm species found in Vermont have probably come into North America by early colonial trading with Europe. These  worms are in the family of Lumbricidae. The new invaders are from East Asia and are in the earthworm family Megascolecidae. There are several Amynthas species in the North East. These species are usually called Jumper worms (Alabama Jumpers), Wrigglers (Jersey Wrigglers) or Snake Worms. It is difficult to differentiate among these species by looking at their external appearance. One needs to look at the internal organs of these worms to tell which species they are. The only Amynthas species found in Vermont to this date are Amynthas agrestis.

These worms are very aggressive invaders that change forest structure and the

Forest on left is earthworm free. The one on the right is invaded by Amynthas agrestis. Dear may make the situation worse by browsing on whatever is still there after the earthworms have done their damage.

Figure A2: Forest on left is earthworm free. The one on the right is invaded by Amynthas agrestis. Deer may make the situation worse by browsing on tree seedlings because earthworms have reduced browse in the forest understory.

decomposer community in the affected forests. This may have long range effects on these forests (Figure A2) including a reduction in forest regeneration. Just imagine a world without maple syrup … Because of the devastating effect on the forest floor vegetation, some other organisms such as ground nesting birds are affected as their nests are no longer hidden from nest predators. Our lab is trying to find where these earthworms are in Vermont although we frequently stumble upon them by chance. The range of this earthworm in Vermont as we know is shown in Figure A3. We ask for your help to find as many places that have been invaded as possible: if you have seen them at your house or a forest near you let us know

Known distribution of Amynthas in Vermont

Figure A3: Known distribution of Amynthas in Vermont

by adding a blog comment which should include an address or the coordinates of where you have seen them. At your home look at mulched flower beds, compost piles, and adjacent woods. Other places where you might find them are nurseries and mulched beds in your local park, community garden and parking lot. I found them in the oddest places. For example, they were happily snaking around in mulched beds of a parking lot in Colchester and the ornamental beds of the Williston I89S rest stop. And yes, I have them  at my house too and curse them every time I buy more mulch for my ornamental beds. They love mulch and go through it as though there was not tomorrow. Eventually you get wise and stop feeding them that mulch. Yes, they can decompose woody mulch. They stimulate the production of lignin decomposing enzymes (Figure A4). You even see them in decomposing logs.


Figure A4: Peroxidase ( a lignin decomposing enzyme) activity in Pine (P), Spruce (S) and Cedar (C) mulch with A. agrestis (dark bars) and without A. agrestis (lighter bars).

Here is when to look for them: The best time to find them is from end of June to mid-October (Figure A5). That is when they are most abundant. They hatch in April around these parts when temperatures have risen above 50 F for the first time but you won’t be able to see their tell-tale saddle or clitellum that stretches all the way around the circumference of their body (Figure A1) until they are adults. You can tell them even when they are still juveniles and don’t have that saddle. They tend to squirm a lot, move like snakes and sometimes lose their tails in an attempt to get away from you.


Figure A5: Amynthas agrestis through the year. They hatch in April and die with the first frosts in Autumn. The first adults are seen in July.

The following link has a video of the Crazy Snake Worm slithering around mulch in a podcast by Vermont Public Radio PR on earthworms in Vermont in general:

April 7 and 8, 2014: Last week we collected temperature data at the horticultural Research Center (University of Vermont) in South Burlington. Soil temperatures stayed at or below 0 C from January 25 to April 1, 2014 (blue line, Figure A6) even though there were large swings in ambient temperature (red line). This was probably due to snow cover. Unlike in other years, the soil was frozen. Ice reached to a depth of approximately 4 cm.

temperaturetilll April12014









April 8, 2014. We went to an Amynthas-invaded forest site in Huntington where, to our surprise, we found  a lot of potential hatchlings which are now being incubated in the lab at 15 C. We found them in the leaf litter both under snow and patches where the snow had already melted. Soils were still frozen and temperatures in the leaf litter were 4 C and under the snow 1 C. Ambient temperatures at 2:30 pm were 9 C. The suspected hatchlings were in water films on and between leaves. Pictures below shows Korkmaz Belliturk and Josef Gorres at Huntington today (picture credit: Naomi Cunningham).


February 12, 2014. We counted the hatchlings from Huntington. We found 111 potential hatchlings on leaves collected from 6 quadrats that were 20 by 20 cm in size. That translates into approximately 400 hatchlings per square meter or 40 per square foot. Since collection of these hatchlings they have been growing in the cool temperature incubator. On February 10 we surveyed the invasion site at the Horticultural Research Center at UVM. We only found 1 potential hatchling in 5 plots of 30 cm X 30 cm area. This site was dryer than Huntington.

42 thoughts on “Amynthas agrestis: The Crazy Snake Worm

  1. Dear Josef,
    I have been wondering about the large, fast-moving worms in the flowerbeds at the Starksboro Public Library on Rte 116 in Starksboro. I believe they may be the worm you describe above. We planted this bed a few years ago – perhaps 5 years. Originally it was very poor soil and we added a load of compost, planted some perennials and shrubs from Rocky Dale and Cobble Creek, and some perennials from our gardens. We first mulched with some of the electric company’s leavings from chipping trees. This year we added a load of mulch from Greenhaven. So, we don’t know where the worms came from, and there are many possible sources from this planting history. I just collected a bunch to use for a worm class I’m teaching and couldn’t find anymore bait worms at the stores. I will be sure to put these back in the library beds, and not in the forest! I am glad to find out about these so we can be more careful. I’ll be interested to learn more from you. Thank you. Chris

  2. I was just searching for this info for a while. After six hours of continuous Googleing, finally I got it in your website. I wonder what is the lack of Google strategy that do not rank this type of informative sites in top of the list. Normally the top sites are full of garbage.

  3. Found at 389 Quarry rd in Washington, Pennsylvania on this date and time… moves like a snake in water and on land, has rigid rings on body, unlike earthworms, and fell apart while being handled… I am astonished at this find!!!

  4. I found these worms in my plot in our community garden at North Branch Nature Center in Montpelier, VT, last fall. This year there are copious amounts of them. I gathered at least a hundred in a bed the size of 1 by 3 meters. I am going to stop using leaf and newspaper mulch for the winter and rather try covercrops. I would love advice on how to minimize their presence and help stop their spread into the forest.

  5. Hello,

    I’ve also seen these crazy snake worms at my home in Framingham MA. I have a patio that I was trying to clean up because of growth in between the bricks and when I started scrapping between the bricks these worms started coming out of the bark mulch that surrounds the patio. They were aggressively coming at me. I jumped up took a rake and flung them into the grass and moved to the middle of the patio to get further away from the edge. It happened again and I stopped because as soon as I made sound they came at me and I had to jump back, grab the rake to scoop them up to remove them from the area. Because they weren’t behaving like ordinary earth worms I did a search that got me to this site. If there is a way to get rid of them please let me know. This has also taken a toll on my grass. Does it help to remove the bark mulch and not use bark mulch at all?

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  8. Hi, I am finding these crazy worms in my community garden here in Boston. This was the first year I’ve seen them! I would love some recommendations on how to get rid of them. Nichole

  9. Hi Josef
    We have them in Rochester Vt, they were freakin’ me out when I was pulling up flax. Big sumo thrashing-around worms, ick. Probably came in on cow or horse mulch. If you find a way to kill them off let us know!

  10. I have had these worms for years and knew they were not the large nightcrawlers that we used to use for fishing.They have turned my soil into crumbles of dried dirt that has no water retaining ability. My raised vegetable garden is decimated of any organic matter and is almost like trying to garden in concrete. I would love a solution to rid my soil of these worms. For years, no one knew what I was talking about until the guy that runs the Maine Botanical Garden (can’t remember his name) wrote an article about these worms and said that they were more worrisome than the extinction of the honey bee. They are a curse to gardening!

  11. I believe that my Chicago (north suburban) garden is infested with these worms. I find them under the mulch on certain garden beds and under the large bark pieces I used on woodland paths and around the base of two maple trees. They do not appear in my vegetable garden. I can’t find any information about their occurrence in Illinois, nor methods to combat them in my organic yard and garden that contains areas of woodland and prairie wildflowers, five on-ground compost piles, lawn, ferns, vegetable and herb gardens, etc. Please let me know of any advice you may have, and thank you for this article.

  12. In late July this year my lawn suddenly started wilting, and it looked like the grass clippings I’ve been leaving on the lawn when I mow were killing the grass. I’ve been following my organic lawn care co’s instructions (mowing high, leave clippings on, throw on new grass seed, water) so I was not happy with all these dead spots in my lawn. The lawn care company suspects “snakeworms,” and they may be right.
    As I pulled out a plug of crabgrass very large worms were on the surface. I guess that could explain the sudden die off. What to do?

  13. Our Nature Center here in CT gave a lecture on these crazy snake worms, and when someone asked how to rid the garden of them, he said sevin dust could be put down end of March or early April when the young ones emerge. Do you have another suggestion?

    Thanks very much!

  14. HI John,

    Most of the worms at this point in the year are about to mature. I guess another week and you have the first that are able to reproduce.

    It is difficult to determine the species. You need to cut them open and check where the organs are, how many of certain organs there are and what shape they are. Not easy without a microscope and a dissecting kit.

  15. There are somethings you can try. For example heat the soil with black plastic sheeting. There is also a fertilizer that seems to be anirritant to them that may lead to their demise (its called Early Bird). The liquid version seems to work even when diluted 1 part to 20 parts water.

  16. HI Adam,

    Interesting. Most likely it is a different worm. There are some that are aquatic. I am not familiar with those species. Sorry.


  17. HI Flo,

    Hm, good question. I don’t know the answer to that. Amynthas lives close to the surface and moles mainly below the surface. Moles will eat earthworms. Not sure about Amynthas.

  18. HI Scott,

    These earthworms will die at 100 F or so but it is unlikely they stay in place in a hot pile. The move quickly and likely they will find a spot near the surface of a compost pile that is closer to ambient temperature.

  19. I have millions of these worms in the forest next to my house.. Trying to experiment using them in a worm farm, they seem to make very nice worm casings

  20. I live in Broken Arrow Oklahoma. Yesterday, (March 13th), I found over 150 of these worms. It was raining all day and the ground was flooding so the worms were being forced out of their burrows. Their behavior when you tried to pick them up freaked me out at first, but it also made me curious, so I started doing some research online. That led me to this site. I always thought seeing earthworms in your garden and yard meant you had healthy soil. Now I am concerned after reading this article. Is there a way to get rid of these pests? I am worried that finding over 150 worms in about two hours could mean my entire yard is infested. Do you have any advice?

  21. We know cold has really no effect on the hatchlings. How do you thing the worm would handle the 135-140 degree temperatures required for the USDA APIHS testing?

  22. Hi Josef,
    I recently completed your survey on Amynthas agrestis. Are the moles in my yard and gardens likely to eat the AA?

  23. I live in a suburb south of Pittsburgh. I was cleaning the leaves out of the botton of my pond (does have mulch around it) when I found 3 of these. They are large, the largest is around 9″. Their ring looks exactly like your photo’s, bug their bodies are so white the’re almost clear/opaque. I guess from the water? I wasn’t sure what I had found and started searching images, that led me here…

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  25. I’ve been finding Crazy Snake Worms in my gardens for the last few years (I live on a wooded lot in North Gorham, Maine and have extensive shade gardens with perennials, shrubs and trees. I was holding one to show my husband the other day and it reminded me of a leach the way it’s end was behaving. I was planting a perennial this summer and when I pushed my shovel into the ground one of these earthworms literally shot vertically out of the ground and was airborne!!! I’ve never seen such a thing! I was speaking with a friend in Gray, Maine yesterday who has similar earthworms in his gardens. I’ve read about invasive earthworms that can alter entire ecosystems because of the way they burrow and the speed at which they consume organic matter. Is there anything I can do to slow their infestation or has Pandora’s Box been opened and it’s too late to do anything to control the population?

  26. I sighted of which I believe to be a (Amynthas Agretis) Snake Worm. I had never seen such an aggreseve animal resembling a night crawler! It was wrigling down a hot sidewalk at probably in access of 110 degree F if not more. I attempted to pick it up, to help it back into the grass. To my surprise! It quickly sprang from beneath my finger at a high pace or wrigle! It took off down the hot sidewalk! WOW! I had to check this wild little creature out. For sure! Not a night crawler, or what I know as a common earth worm.
    I cautiously fallowed, and observed. It had no apparent head, so I assumed it was not going to bite me, so I attempted to pick it up again. It jumped! It wriggled frantically! It fled away couple more times. Finally got hold of it! It was so strong I could hardly keep it between my thumb and index finger. I quickly pitched it into the grass lawn along the sidwalk! It just as quickly vertically vanished into the lawn.
    This observation, was in Escondido, California at the corner of Ash st. & Valley Parkway. That little critter really got my curiousity up! WOW ÷).???

  27. I have these in my back yard in Webster, MA in DROVES!!! Like, I dug in a 2ft square area and was literally grabbing them in HANDFULS! I use them for fishing bait. Had no idea they were an invasive species.

  28. Hi Josef ~

    Any updates on the growth of the worms since your note of May 3rd?

    We now have people who say that they have seen A. agrestis in various communities in our area in the past, but I don’t know how they determine the genus and species, so more research is indicated.

    Best wishes,


  29. Dear John,

    Those are really good questions. I am incubating some juvenile earthworms found at a site with Amynthas agrestis that are very small (2 cm) to see what they really are. If these are A. agrestis then you can forget the 50 F figure because we found them in meltwater between leaves. The temperature there was 38 – 40 C.

    Good question too about whether these earthworms die when it gets colder. May be the juveniles have other defenses against the cold, maybe some salts in their bodies that depress the freezing points. Just a speculation, no fact about it at all.

    I will know more when the incubations are successful and I can identify these earthworms. Lets see maybe in three weeks we will know more.


  30. For the crazy worm to hatch, does it just need to get above 50 sometime during the day, or is there a certain number of hours for which 50 degrees needs to be exceeded?

    Also, what happens if, it say, gets to 60, but two days later, it gets down to, say 26? Do the hatched worms die? We have 5 days in a row above 60 and then 3 days in a row where the highs/lows were 42/26, 37/18 and 52/27.

    Thanks much,


  31. HI Sandy,
    I am going to conduct some experiments with a fertilizer that contains some saponins that have been detrimental to other earthworms. I wonder whether this product is going to be effective on the crazy snake worm.

    I let you know if it works. I have to wait a couple of months before I try that control strategy cause they are just hatching now. Temperatures are spiking about 10 C (50 F) which appears to be the trigger temperature for them. It could be that soils need a few days longer to reach that temperature after the atmospheric temperature goes beyond 10 C. When they first hatch they are very small thread like creatures. Difficult to find. So we wait for the experiment till they are 3 to 6 cm long ( 1- 2 inches).

    I keep you in the loop.

  32. I live in the Redstone Quarry section of Burlington. Last year I put a lot of mulch in my raspberry patch and that is where I have most noticed them. After reading your article, I will remove the mulch and try to remove the eggs as soon as I can this spring.

  33. Hi Sandy,

    Do you remember where in your yard you saw them. Which part of Burlington do you live in? Burlington is riddled by these earthworms. I find them in many places… Thanks for your comment.

  34. I first noticed these worms in my garden two summers ago. I am very afraid of snakes and noticed that these “night crawler” sized worms were acting like snakes. My friends at first thought I was just being paranoid but then they saw them. They tend to hang out in taller grass or as your article mentions, mulched areas. I would like to try to get rid of them but will probably need to enlist friends who don’t have my fear. If there is something else that I can do, please let me know. I live in Burlington, VT.

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