Jumping worms have been in the United States since the 1800’s and in Massachusetts since at least 1953. During the late summer months of 2021, the Plymouth County Extension office received an excessive number of calls regarding these worms. Looking back over the temperatures from the winters of 2019-2020 and 2020-2021, they realized that we had exceptionally warm winters. Unlike their European counterparts, the Asian jumping worms devour organic matter more rapidly, stripping the forest floor of the layer critical for seedlings and wildflowers. 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. These invasive worms can severely damage the roots of plants in nurseries, gardens, forests, and turf. They, along with other invasive worms, can also help spread invasive plant species by disturbing the soil.
The Asian jumping worm has a prominent band around the body of the worm, called the clitellum, where cocoons are produced. The band completely encircles the body, is milky white to light gray, and is flush with the body; the body looks metallic. On European nightcrawlers, the clitellum is raised or saddle-shaped and reddish-brown in color and does not wrap entirely around the body. Jumping worms move in a snake-like, zig-zag manner on the ground, moving side to side. The European earthworm slides the front part of the body forward, which is followed by the back part of the body. Adult jumping worms are active and lay their eggs during the warm weather months, and die after a frost. The cocoons hatch whenever the weather turns warm - above 50 degrees - for a consistent period. However, if the temperatures drop below 41 degrees, the newly hatched worms die. And the cycle continues. The worms emerge if the temperature rises, and they die if the temperature falls. The good news is many jumping worms that had emerged in the past extremely warm January died this winter during the sub-zero temperatures we had in February. One telltale sign of an infestation is a very uniform, granular soil created from worm castings. The texture of this soil is often compared to coffee grounds. When you scratch the top layer of soil you will see the worms thrashing about with an erratic, snakelike movement. These worms, which can reach 6 inches in length, are much more active than European nightcrawlers.
The Asian jumping worm can be found on the soil surface and in the leaf litter, making them easy to find. So, gardeners, breathe, and don’t stop gardening. If you do have jumping worms, you are not a bad person who was not careful enough, because there are no barriers between gardens. Collect any worms you find and 1) drown them in vinegar or 2) put them in a plastic bag straight into the trash, or put the plastic bag in a sunny spot for 3 days then put into the trash. These worms like compost and bark mulch, so be sure to purchase from a reliable source that uses solarization (the mulch reaches a temperature greater than 130 degrees F. for more than 3 days). They dislike pine needles. Birds and centipedes are natural predators, but not in the numbers we need to bring this under control. Bare-rooted plants are safer, and that is why we are removing all soil from our plants before selling to the public.
Cornell Cooperative Extension Invasive Asian Jumping Earthworms Invasive Asian Jumping Earthworms - Author: Sandy Vanno, Master Gardener Warren County CCE Nearly all earthworms in the Northeast today are non-native, and European and Asian invasives are altering the soil structure and chemistry of our forests. Asian jumping worms are a relatively new invasive species, but they are rapidly spreading across the United States. They can be found in the Southeast, along the Eastern Seaboard, and in the mid-Atlantic, Midwest, and some Northwestern states. The first records of Asian jumping earthworms date back to the late 19th century; unfortunately, relatively little is known about them compared to European earthworms. European nightcrawlers are now being displaced by the destructive Asian jumping worms. There are actually at least three species: Amynthas agrestis, Amynthas tokioensis, and Metophire hilgendorfi that co-occur. Asian jumping worms devour organic matter more rapidly than their European counterparts, stripping the forest of the layer critical for seedlings and wildflowers. 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. These invasive worms can severely damage the roots of plants in nurseries, gardens, forests, and turf. They, along with other invasive worms, can also help spread invasive plant species by disturbing the soil. Asian jumping worms are an annual species; the adults die after the first freeze. But the cocoons, which are about the size of a mustard seed, will survive the winter and hatch when temperatures reach 50°F for a consistent period. One worm can produce many cocoons without mating. Because they are more aggressive and their populations can grow faster than the common European species, they may out-compete existing worm populations. 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, on landscaping equipment, mulch, tire treads, and even hiking boots. One telltale sign of an infestation is a very uniform, granular soil created from worm castings. The texture of this soil is often compared to coffee grounds. When you scratch the top layer of soil you will see the worms thrashing about with an erratic, snakelike movement. These worms, which can reach 6 inches in length, are much more active than European nightcrawlers. The Asian jumping worm 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 also very likely to find them in compost piles and along roads. The Asian jumping worm has a prominent band around the body of the worm, called the clitellum, where cocoons are produced. The band completely encircles the body, is milky white to light gray, and is flush with the body; the body looks metallic. On European nightcrawlers, the clitellum is raised or saddle-shaped and reddish-brown in color and does not wrap entirely around the body. Asian Jumping Earthworm - Wisconsin Department of Natural Resources How do you stop the spread?
There are currently no viable jumping earthworm control methods, although research is continuing and we can 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, avoid moving plants or soil from your yard.