Recently, an invasive worm species originating from Asia has been spreading rapidly across the United States, causing significant concerns for the local population.
This spring, numerous reports documented the unusual presence of “jumping worms” (a species from the genus Amynthas) in areas such as Maine, Missouri, and California.
Jumping worms resemble earthworms but have lighter-colored clitellum positioned closer to their head. They inhabit the top few centimeters of soil and range in length from 3 to 22 centimeters. This species is called “jumping worms” due to their quick and jerky movements.
The invasive worm species is spreading across the U.S. with peculiar movements.
While earthworms are considered beneficial for soil, jumping worms pose a threat to farmers. Jumping worms extract nutrients from the soil, leading to nutrient depletion and increased erosion. Additionally, they threaten the growth and survival of earthworms, putting this species at risk of extinction.
Despite the dense proliferation of jumping worms being a concern, scientists indicate that this species does not cause significant damage to U.S. agriculture.
Experts note that gardens and fields are not ideal habitats for jumping worms. This is because these worms cannot burrow deep into the ground to escape heat like earthworms and are prone to drying out in high temperatures (above 30 degrees Celsius). This means that as jumping worms continue to spread across the U.S., they will likely congregate in cooler, shadier areas such as forests, rather than in agricultural fields.
“The primary damage they may cause is in forested areas. When jumping worms inhabit cooler hillsides and forest floors, the topsoil is more susceptible to erosion,” said Lee Frelich, director of the University of Minnesota’s Center for Forest Ecology.
Shady forests are ideal areas for jumping worms to thrive.
Frelich recounted that earlier this May, a small rainstorm washed away over 5 cm of topsoil in his university’s nursery. This could be attributed to the invasion of jumping worms.
Frelich explained: “Erosion poses a threat to forest ecosystems in hilly areas. Moreover, worms burrowing through the soil can displace seeds, hindering their germination and rooting. Even when seeds have developed into seedlings, the presence of jumping worms can attract worm-eating animals like wild turkeys, which tend to uproot plants in search of worms, ultimately reducing the amount of green vegetation over time.”
Jumping worms can only move a few dozen meters in a year and primarily spread through organic mulch on the surface. This means that urban areas using mulch in gardens are currently the main targets for jumping worms, rather than wild areas. However, with human activity, this worm species could expand its range in the U.S. and access even more ecosystems.
Frelich noted: “Many people enjoy fishing and often use jumping worms as bait. This inadvertently gives the worms a chance to proliferate in remote areas and forests.”
Typically, jumping worms hatch in the spring, but in some states like Wisconsin, many have reported continuous reproduction of this species during the winter, as temperatures have trended higher than in previous years.
The U.S. Department of Agriculture warns that if jumping worms continue to proliferate in large numbers, many plant species may disappear.
In light of the widespread emergence of jumping worms, Mr. Bernie Williams, a pest management specialist at the Wisconsin Department of Natural Resources, has provided several measures to help residents prevent and eliminate this pest.
According to Williams, the worms are relatively easy to eradicate. They breathe through their moist skin, and losing moisture means death. Therefore, we can simply leave them on a concrete or brick surface in sunlight, and they will die within minutes. Additionally, insecticides are an option if the worm population is too large.
Jumping worms are easy to proliferate but also easy to eliminate.
“If you suspect there are jumping worms in your garden or see the soil clumping like coffee grounds, you can scoop a shovel of soil, put it in a bucket, and fill it with water. Wait a few hours; if there are jumping worm cocoons, they will float to the surface,” Williams added.
Unlike earthworm cocoons, which are yellow and visible to the naked eye, jumping worm cocoons are harder to identify and nearly invisible in the soil. Upon closer inspection, they resemble broken black beads.
Frelich advises the public to avoid inadvertently moving worms. To prevent the spread of worm cocoons, regularly clean gardening tools, footwear, and tires. When purchasing organic mulch, residents should choose mulches and compost that have been heated above 40 degrees Celsius to eliminate jumping worm cocoons. With community cooperation, the spread of jumping worms can be quickly curtailed.
