Invasive Spotlight: Asian Jumping Worms
Most earthworms present in glaciated portions of Ohio are considered exotic. They were introduced in the 18th & 19th centuries by early settlers or through trade of soil and horticultural materials transported from Europe and Asia. New species are continuing to be introduced spreading through fishing bait, compost and gardening supplies, and plant exchanges. In SW Ohio, we consider one non-native worm, the European Nightcrawler as a friend to our gardens. This is not the case for our latest invasive worm, the Asian Jumping Worm. Also known as crazy snake worm, Alabama jumper, and Asian worm.
Unlike their European counterparts which burrow deep beneath the forest floor, jumping worms stay on the surface, rapidly consuming leaf litter and turning the once cohesive mass of soil into grainy, dry castings. These castings look like dry coffee grounds, easily erode, and cannot support many native plants. One study found that jumping worms can eliminate up to 95 percent of leaf litter in the forests they invade.
Once let loose, jumping worm invasions are hard to contain. Where most European worm species move about 30-feet per year, jumping worms can easily cover 17 acres, or roughly the size of 13 football fields, of new ground in a single season (study by the University of Wisconsin).
Jumping worms grow twice as fast, reproduce more quickly, and can infest soils at high densities. In areas of heavy infestation, native plants, soil invertebrates, salamanders, birds and other animals may decline. Jumping worms can severely damage roots of plants in nurseries, gardens, forests, and turf.
Where to find them?
They can be found on the soil surface and in the leaf litter, making them easy to find. They can live anywhere from urban parks and suburban backyards, to rural forests. You are very likely to find them in compost piles and along roads.
All Jumping Worms look very similar, but there are actually at least three species: Amynthas agrestis (which is most often cited), Amynthas tokioensis, and Metaphire hilgendorfi.
We know that species co-occur, but not enough information is known about the distribution of each species and their respective impacts. Mature jumping worms can be identified with the following parameters:
· Color: Smooth, glossy gray or brown
· Length: 1.5 to 8 inches long
· Clitellum (the narrow band around their body, near the head of the worm): Smooth to the body, unlike most other species which have a raised pink colored band. The clitellum encircles the body, unlike the saddle shaped band on a European Nightcrawler. The band’s color is often milky white to gray colored.
· Behavior: They jump and thrash wildly when handled, moving more like a threatened snake. They can also shed their tails in defense.
· Soil changes: Jumping worms leave distinctive grainy soil full of worm castings. The soil becomes granular and looks like dried coffee grounds.
· Timing: Best time to find them is late August or September when they are at their largest. Adults die prior to winter, but their young survive harsh winters in tiny, resilient cocoons. Cocoons are very small and dirt colored, so they are nearly impossible to spot with your own eyes. Cocoons can be spread easily in potted plants, and on landscaping equipment, mulch, tire treads, and even hiking boots.
OSU has developed a reporting site where Ohio gardeners can document locations of suspected populations. Gardeners should visit https://go.osu.edu/asianjumpingworms to report suspected locations and upload photographs.
Helpful tips to prevent the spread (provided by Cornell University):
Do NOT buy or use jumping worms for bait, vermicomposting or gardening.
Dispose of all live worms in the trash or place them in a bag and leave out in the sun for at least 10 minutes. Then throw bag away.
Only sell, purchase or trade compost that was heated to appropriate temperatures and duration following protocols for reducing pathogens.
Find out more
· Book: Earthworms of the Great Lakes by Cindy Hale. Earthworms of the Great Lakes will not only help you identify 16 species that are found in the ground beneath your feet, but it will also educate you as to their role in our forest ecosystems.
· Jumping Worms Factsheet by Cornell University http://ccetompkins.org/resources/jumping-worm-fact-sheet
· Asian Jumping Worms a threat to Gardens and Woodlands, by OSU Extension. https://bygl.osu.edu/node/1679
· Voracious Asian jumping worms strip forest floor and flood soil with nutrients, By University of Wisconsin https://www.sciencedaily.com/releases/2016/09/160908171315.htm