There’s Something in the Soil: Invasive Jumping Worms!

Getting out in the garden is something we look forward to each Spring. This year, you might find something you didn’t expect…worms that jump! Well, perhaps thrash wildly.

The first time I heard about this, I thought it was a joke. My friend, who lives in Pomfret, posted on Facebook how he was trying to kill all the jumping worms he found on his forested property. I, along with his other friends, thought he was kidding and we tried to tell him how good worms and castings were for his garden - but he wasn’t persuaded.  This is what my friend, Dave Bielski, had to say: 

“The first sign we saw of jumping worms were massive piles of worm castings in our lawn.  We had seen them before, and assumed they were from regular nightcrawlers.  A fellow gardener warned us that we could have invasive jumping worms.  We then set about trying to determine if we actually had them.  Our first confirmed jumping worms were found in the leaf litter adjacent to our lawn.  We soon realized we had them everywhere, in our raised beds, in the lawn, and in the woods behind our house.  From a gardening perspective, we realized we were having trouble growing certain squashes in recent years due to nutrient depletion in the soil.  We now understand that the worms have been a problem for a few years now.  We are now using diatomaceous earth in our raised beds, to see if we can control them in our vegetable gardens.  Time will tell.”

Amynthas agrestis, (aka “crazy worm”, jumping worm”, “crazy snake worm”) were first found in patches in southern and central Connecticut in 2015, but they are quickly expanding their territory and can now be found throughout Connecticut. They are a species of worm in the family Megascolecidae and trace their origins back to East Asia. They are not only associated with urban and suburban areas but can also be found in forested landscapes. Once established in an area, they grow and mature quickly. There are a few different species, and some are even asexual, which can also contribute to their high densities.  The jumping worms only live one season, but they produce very small, 2-millimeter cocoons that survive the winter and hatch in March.

So aren’t worms good for the soil? Yes, but these are invasive worms that can transform soil into what looks like gravel, or “macroaggregates” with their castings. My friend was upset because they are endo-epigeic, meaning they only live at the very surface of the soil and they don’t aerate the soil or provide any nutrients or pockets of water at the plants’ roots. 

In addition, this gravelly texture can cause leaching of nutrients, soil erosion, and root desiccation making it inhospitable for other plants. The worms also eat mycelium (the fungi in soil that breaks down and absorbs organic matter to make nutrients for plants and fauna), so any plants that rely on symbiotic mycelium for nutrients will be out-competed and die off.  And if all that’s not bad enough, the worms displace earthworms and are not particularly nutritious for birds.

Here’s how you can identify these invasive worms:

1. Thrashing behavior and high densities

2. 1-½” to 8” long.

3. Smooth, metallic sheen, often darkly pigmented (grown, grey, purple) and 1.5 to 8 inches long. A key identifier is a smooth cream-colored clitellum that goes all the way around the body located towards one end instead of the middle of the worm. The clitellum is a thick ring found on the skin of the worm, usually with a light-colored pigment. Earthworms have a raised pink clitellum and don’t go around the entire worm, like a saddle.

4. “Gravelly” soil

    

Courtesy of State of Connecticut Publications

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

How do you stop the spread? Here’s some information that might help, courtesy of Cornell University:

There are currently no viable jumping earthworm control methods, although research is continuing and we can do to prevent their spread:

• Do not buy or use jumping worms for bait, vermicomposting, or gardening.

• When purchasing bulk mulch or compost, use a reputable producer that has heat-treated the material to a temperature of 130°F for at least three days to destroy the cocoons or purchase bagged mulch.

• Check your property for jumping earthworms using a mustard pour (it won't harm your plants!). Mix a gallon of water with 1/3 cup of ground yellow mustard seed and pour slowly into the soil. This will drive any worms to the surface where you can easily remove them.

• Cocoons are sensitive to heat and can be destroyed with clear plastic solarization; in late spring or summer, cover moistened soil with a sheet of transparent polyethylene for two/three weeks or until the soil temperature exceeds 104°F for at least three days.

• Be careful when sharing and moving plants; always check for worms and know where your plantings come from; buy bare root stock when possible.

• If you have a small population of jumping worms, handpick and destroy them by bagging them and throwing them in the trash, or place them in a bag and leave out in the sun for at least 10 minutes; then throw the bag away.

• Research is currently being conducted on invasive worms at the University of Wisconsin and several practices do show some promise of control. Abrasive materials such as biochar (ground-up charcoal) and diatomaceous earth (fossilized diatoms) may show some promise in killing adult jumping worms. Incorporate one of these products into the infested soil to a depth where the worms are located; worms that come in contact with the materials will be adversely affected.

• If you have jumping worms, report them (www.nyimapinvasives.org) and avoid moving plants or soil from your yard.

Judy Konopka

Commissioner, Middletown Commission on Conservation and Agriculture