Snake Worms
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Snake worms are a type of invasive worm that have become problematic in our CT landscapes.
The worms that we call crazy snake worms, jumping worms, Asian jumping worms, Alabama jumpers, and other names are these three:
Amynthas agrestis, Amynthis tokioensis, and Metaphire hilgendorfii
They are distinguished from the worms that we have always had in our gardens by their larger size, the fact that they jump and leap when disturbed, and by specific identifying body parts that enable you to identify them. They can be 4-6” up to 8” long and have a flat, milky white band (the clitellum) that completely encircled their body. Google their scientific names and you will find excellent pictures and illustrations to use as reference. A few links are included with this handout.
One way to know that you have these snake worms is to notice their behavior when you uncover them while gardening. Another way is to look for their worm castings which look like crumbly, small gravel-like chunks. Some compare them to coffee grounds.
These invasive worms digest organic matter very quickly and cause erosion, root decline, and destroy the organic soil structure which inhibits seed germination. They primarily live in the leaf litter and top 2” of the soil and digest the organic matter, causing erosion. The soil food web is destroyed and what is left is a mineral soil. Invasive plants often thrive on this type of low organic matter soil.
If you notice that the native understory plants in your woodland garden have been disappearing, you may have a snake worm infestation. They can also migrate into your garden beds. If you apply compost and mulch, it will be digested and disappear very quickly. Plants will start to shrink instead of growing and when you dig them up, you will find greatly diminished root systems.
Snake worms were originally brought to the New York City from Japan. They escaped and now are found throughout New York, CT, and our entire region.
Understand the snake worm life cycle
In April the cocoons hatch and the juvenile worms quickly grow. By mid-June they have become adults and live in the top 2 inches of soil, decomposing organic matter, throughout summer and fall. In late fall, the worms produce tiny cocoons (poppy or mustard seed size!) which then live in the soil throughout the winter. The cocoon bank can last up to two years in the soil. These worms do not need a mate to reproduce.
If you want to test to see if you have snake worms and, if so, how many, you can mix 1/3 cup of ground yellow mustard seed powder (available in the grocery store) with 1 gallon of water. Pour the solution slowly over an area where you suspect the worms are living. The mustard will irritate them and they will come to the surface. You can then gauge how bad the infestation is. Collect the worms and either drown them in a bucket of soapy water or put them in a plastic bag, seal it, and put the bag on pavement or a hot surface for at least 10 minutes, then toss in the trash.
There are no products currently certified to treat soil infested with snake worms.
Solarizing the soil is one option to control their numbers. It is best done during the heat of our long summer days. Buy a clear plastic painter’s tarp and spread it on the soil. Add a 6-8” layer of the snake worm-infested soil. Top with another layer of plastic and seal the top and bottom layers together by folding together and closing the “tarp sandwich” with duct tape. Be sure it is held down tightly so no worms can escape. Leave it on that spot for at least 3 days. Temperatures must reach 105 degrees for three days to kill the worms.
Snake worms are spread in soil, mulch, compost, in waterways, in yard waste, on tire treads of wheelbarrows, mowers, and yard equipment, on soil in the treads of your boots, on tools, and by those who unknowingly buy them and use them as bait.
The Natureworks Policy
Natureworks sells plants produced by trusted growers who use sterilized soil that, to our knowledge, do not contain snake worms or their cocoons. We also sell bagged composts and soils that are heat treated to 140 degrees to kill snake worms.
Precautions you can take
Plant exchanges and sharing plants with other gardeners is often the way that snake worms are introduced to a yard. Learn to recognize their castings and ALWAYS inspect any plants that you get from friends or plant swaps and local sales. If in doubt, rinse all of the soil off and discard and repot into clean, sterilized bagged soil.
Don’t share tools and gardening equipment unless it is thoroughly cleaned first.
Wash and sterilize any pots that you plan to reuse. In the spring, the snake worm cocoons are tiny and may not be noticed. Don’t take any chances.
If you are gardening in a yard that has snake worms, wash off all your equipment and your boots before leaving.
Be on the lookout for the signs of a snake worm infestation and take action immediately if you suspect it.
Biochar
Natureworks has been experimenting with biochar to help control snake worms. This is not scientifically proved, but rather, anecdotal evidence from our own experiences. We add biochar to gardens and are constantly observing the effect of this soil amendment on the snake worm population. Research is presently being done at the University of Vermont and other institutions on the use of biochar for this purpose. Stay tuned.
Gardening Practices
If you discover snake worms in your garden, stop adding compost and mulch to feed the worms for one season. You can add targeted, small amounts of granular organic fertilizer to heavy feeders directly around the root zone or use liquid organic fertilizers. Add biochar by sprinkling it on the soil and working it into the top 2”. Continue this practice for a second year or longer. Consider replacing mulch with a ground cover plant layer as the soil recovers.
Do not bring home composts and mulches from town dumps unless you know the pile heats up to 140 degrees when composting.
Leave any materials you do bring onto your property on a paved surface in a thin layer (6-8” deep covered with clear plastic for 3 days to kill the worms.)
If you collect and kill worms, dispose of them in sealed plastic bags in the garbage. Never throw them back on the soil. If you drown them in soapy water, strain the water through cheesecloth and toss the cheesecloth as described above. Never dump the water on the garden.
https://www.uvm.edu/sites/default/files/Extension-Master-Gardener/Josef_Intro_to_Snake_Worms.pdf
https://ag.umass.edu/landscape/fact-sheets/jumpingcrazysnake-worms-amynthas-spp
In an effort to provide horticultural information, these educational documents are written by the Natureworks Staff and are the property of Natureworks Horticultural Services, LLC. You are granted permission to print/photocopy this educational information free of charge as long as you clearly show that these are Natureworks documents.