Invasive Asian Jumping Earthworms (2024)

Invasive Asian Jumping Earthworms - Author:Sandy Vanno, Master Gardener Warren County CCE

Nearly all earthworms in the Northeast todayare non-native, and European and Asian invasives are altering the soilstructure and chemistry of our forests. Asian jumping worms are a relatively new invasive species, but they arerapidly spreading across the United States. They can be found in the Southeast, along the Eastern Seaboard, and inthe mid-Atlantic, Midwest, and some Northwestern states. The first records of Asian jumping earthwormsdate back to the late 19^th century; unfortunately, relatively littleis known about them compared to European earthworms. European nightcrawlers are now beingdisplaced by the destructive Asian jumping worms. There are actually at least three species: Amynthasagrestis, Amynthas tokioensis, and Metophire hilgendorfi that co-occur.

Asian jumping worms devour organic matter morerapidly than their European counterparts, stripping the forest of the layercritical for seedlings and wildflowers. Jumping worms grow twice as fast, reproduce more quickly, and can infestsoils at high densities. In areas ofheavy infestation, native plants, soil invertebrates, salamanders, birds, andother animals may decline. Theseinvasive worms can severely damage the roots of plants in nurseries, gardens,forests, and turf. They, along with otherinvasive worms, can also help spread invasive plant species by disturbing thesoil.

Asian jumping worms are an annual species; theadults die after the first freeze. Butthe cocoons, which are about the size of a mustard seed, will survive thewinter and hatch when temperatures reach 50°F for a consistent period. One worm can produce many cocoons withoutmating. Because they are more aggressiveand their populations can grow faster than the common European species, theymay out-compete existing worm populations. Cocoons are very small and dirt-colored, so they are nearly impossibleto spot with your own eyes. Cocoons canbe spread easily in potted plants, on landscaping equipment, mulch, tire treads, and even hiking boots.

One telltale sign of an infestation is a veryuniform, granular soil created from worm castings. The texture of this soil is often compared tocoffee grounds. When you scratch the toplayer of soil you will see the worms thrashing about with an erratic, snakelikemovement. These worms, which can reach 6inches in length, are much more active than European nightcrawlers. The Asian jumping worm can be found on thesoil surface and in the leaf litter, making them easy to find. They can live anywhere from urban parks andsuburban backyards to rural forests. You are also very likely to find them in compost piles and alongroads.

The Asian jumping worm has a prominent bandaround the body of the worm, called the cl*tellum, where cocoons areproduced. The band completely encirclesthe body, is milky white to light gray, and is flush with the body; the bodylooks metallic. On European nightcrawlers, the cl*tellum is raised or saddle-shaped and reddish-brown in color anddoes not wrap entirely around the body.

AsianJumping Earthworm

WisconsinDepartment of Natural Resources

How do you stop the spread? There are currently no viable jumping earthwormcontrol methods, although research is continuing and we can prevent theirspread:

• 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 it (www.nyimapinvasives.org) and avoid moving plants or soil from your yard.

Jumping worms are prohibited by the New YorkState Department of Environmental Conservation. Prohibited invasive species cannot be knowingly possessed with theintent to sell, import, purchase, transport or introduce.

Resources:

“InvasiveSpecies: Jumping Worms”; ccecolumbiagreene.org

“Look Outfor Jumping Earthworms!”; Penn State Extension; https://extension.psu.edu/look-out-for-jumping-earthworms

Last updated May 14, 2021