Just when you thought you were safe from murder hornets, these flailing, invasive worms make an appearance.
Asian jumping worm, image by Wisconsin DNR
Also known as snake worms, crazy worms, or Alabama jumpers, these worms are not your average earthworm. Of course, they're just worms, and they won't sting you like a murder hornet, but they are just as invasive and threatening to local ecosystems. And they are deadly to the topsoil and plants.
Imagine an eight-inch worm that thrashes "wildly" when disturbed, sheds its tail when threatened, and destroys the soil it lives in. First seen on the East and West Coasts of the U.S., Asian jumping worms (Amynthas spp) were first found in the Midwest in 2013. Since then, they have been spreading throughout the region.
Where are they found?
Since their first sighting in Wisconsin in 2013, the jumping worms have now been seen all across the Midwest, including Illinois, Iowa, Missouri, Indiana, Kansas, Minnesota, Nebraska, Kentucky, and Ohio.
They are all over northern Illinois, throughout the Chicago area, including urban areas and gardens. Fortunately, the adult worms can't survive the cold temperature of a Chicago winter. Unfortunately, their eggs can. The worms lay tiny eggs surrounded by a cocoon that can withstand the harshest winter.
Tiny jumping worm cocoons, image by UW Arboretum
Invasive earthworms
Not all invasive species are bad. All earthworms in North America have come from somewhere else. Over 10,000 years ago, the glacial movement wiped out native earthworms. The earthworms we see in our gardens came here from Europe in the 1600s with the first European settlers.
These European worms, also known as nightcrawlers, benefit gardens by improving drainage and making nutrients easier for plants to access. You know you have fertile soil when you dig up a spot in your yard and find a pile of wriggling earthworms.
However, the Asian jumping worm is the opposite of beneficial. Jumping worms stay in the top layer of soil and eat everything they can find. They will wipe out beneficial organic matter and mulch.
If you've been overrun by these worms you may find yourself needing to replace your mulch multiple times in one season.
Plants and trees need the organic materials that are in the top layer. But the jumping worms eat it all and leave behind hard granules (think coffee grounds) of dirt that contains no nutrients. And now plants can't root in this new soil, and nothing will grow.
Effects of soil from jumping worms, image by Eric Hamilton WI DNR
How to recognize them?
When you are in your garden digging up soil and run into these worms, you will know they are no ordinary earthworm. The first sign is the violent thrashing behavior, which some people describe as looking like tiny snakes.
Chicago's WGN TV segment, featuring Chris Evans, University of Illinois Forestry and Extension Research Specialist
Aside from their movement, they look different than European earthworms. They are about four to eight inches long. The colored band that encircles them is smooth and white. Their skin is glossy, and they might shed their tails in defense.
In contrast, European earthworms move slowly. They may wiggle when disturbed, and the colored band around their bodies is reddish or pink and slightly raised.
You will find them in mulch, leaf litter, and the top few inches of soil.
How to prevent them from spreading
Experts from the University of Illinois Urbana-Champaign recommend that you kill them if you find them. Birds won't eat them as they are apparently too "slimy" and they don't like their taste.
University of Illinois Horticulture Educator Nicole Flowers-Kimmerle recommends placing them in a plastic bag and leaving them in the sun for ten minutes. Then throw the bag out with the trash.
If you do find one, chances are you have more. They tend to occur in large numbers. If your garden is full of them, you can expect to need to replace your topsoil with nutrient-rich dirt often to save your plants.
As of today, there aren't any chemical methods that can remove these pests. According to the Wisconsin Department of Natural Resources (DNR), "Management mainly consists of taking precautions to not move them onto your property. If they are already there, you will need to adapt and adjust until there are better control options available."
The good news is, according to the Illinois Extension, you shouldn't have to worry about potting soils or plants from garden centers bringing in these worms. The soil used for annuals and perennials has been heated to temperatures that are high enough to kill the eggs and other pathogens.
Until research gives us better solutions, our best bet is to remove these worms when we find them.