Have you seen a large active worm in your garden recently? It may be an Asian jumping worm (Amynthas spp), which is an invasive species and they have been having a significant effect on both gardens and forests. Josef Gorres, a professor of soil ecology at the University of Vermont, said that the first jumping worms were found in California in the 1860s and on the East Coast in the 1920s.

Gorres said they feed “voraciously” on organic matter, which results in the reduction of the top “spongy layer” of soil. This can lead to fewer seeds as well as fewer places for seeds to germinate. He also said their castings could get washed out in a big rainstorm, which could also cause greater erosion. In addition, garden plants can also show signs of wilt even if there is enough moisture. According Amynthas spp. Impact on Seedlings are Tree Dependent by Paricia B. Bethke and Meghan G. Midgley, the worms decrease leaf litter and alter plant communities although that can vary among forest types. During a 3 month study they found the worms altered soil structure and they stated that the results “suggested” the worms could alter “forest ecosystem dynamics via seedlings and soil biochemistry.” Gorres said birds and some salamanders do eat them, but they may not be able to eat the adults and it wasn’t enough to keep the population in check.

Adults live through one growing season, but the larvae overwinter and can hatch at 50 degrees Fahrenheit. They develop into adults from 60 to 90 days. Gorres said that in gardens the worms generally mature by June, but in forests they don’t usually mature until July. He said this more moisture and better conditions allowed them to mature faster in gardens. The worms are parthenogenetic, which means eggs development without fertilization. Adults produce one cocoon about every other day, and thus can multiply quickly. Though Asian jumping worms are similar to European earthworms, they have some significant differences. They have a smooth, glossy dark brown color with a clitellum or ring of lighter colored tissue around the body. European earthworms have a clitellum as well, but it doesn’t go all the way around the body. Gorres also said they were more active and agile than European earthworms and thrash violently when handled. The common name of Asian jumping worm actually refers to 16 species of Asian worm and they are also called snake worms, crazy worms, Alabama jumpers, Georgia jumpers, and wood alves.

He said some soaps were effective at killing them and they could be dropped in a bucket of soapy water. In addition, he also recommended posting sightings on http://www.inaturalist.org, though he encouraged people to be sure they have a positive ID before doing so. In addition, vtinvasives.org also recommends soaking them in rubbing alcohol, sealing in plastic bags and being sure to buy only heat- treated compost as well as inspecting nursery plants before putting them in the ground.

Asian jumping worms are one of several invasive species, which are considered a threat to biodiversity. In reducing organic matter, they can make it much more difficult for forests as well as garden plants to thrive. Greater erosion can also lead to reduced water quality and more flooding. However, by checking plants before putting them in the ground and reporting sightings it is possible to slow the spread. For more on invasive species, see my articles on Asian carp from February of 2023 and the spotted lanternfly from November of 2021.