Asian jumping worms, and the majority of earthworms in the United States, are non-native species. We are all familiar with European earthworms like the night-crawler, and don’t generally worry about their presence too much in most environments, and even find their ability to enhance soil structure of yard and garden soils beneficial. However, there are other worms known as Asian jumping worms that impact the soil more than any other worm, which negatively affects yard, garden, and agricultural soils and detrimentally alters forest ecosystems.
Asian jumping worms are native to parts of Japan, China, and the Korean peninsula and are believed to have been accidentally introduced to North America with potted plants, nursery stock, or soil. Since their introduction, they have become widespread throughout much of the U.S. and have recently been documented in northern hardwood forests in Wisconsin, Minnesota, and New York. In NY, jumping worms are known to be present in Monroe and Ontario counties and it is likely they have also infested soils in surrounding counties in the Finger Lakes region.
Jumping worms, as the name implies, are known for their wild thrashing behavior when disturbed. When looking closely at worms, the most identifying way to distinguish jumping worms from other earthworms is by their clitellum (the band around their body). The clitellum of jumping worms is milky-white and flush (or smooth) with the rest of the body. On other earthworms, the clitellum is brown, or similar color to the body, and raised. Asian jumping worms are smooth, glossy gray or brown, and anywhere from 1.5 to 8 inches long.
There are at least three species of Asian jumping worms present in the U.S., although they are very difficult to tell apart: Amynthas agrestis (most common), Amynthas tokioensis, and Metaphire hilgendofi. These three species often co-invade a site, living in the soil and the leaf litter. Jumping worms are often found in urban parks, suburban yards, and forests. Earthworms consume the upper layers of soil, known as organic matter, which supply nutrients for plants and provide wildlife with food, protection, and habitat. Asian jumping worms consume this layer of soil organic matter much more rapidly than European earthworms, depleting forests of the soil layer critical for seedlings and wildflowers. Jumping worms also produce distinctive castings (waste) that resemble coffee grounds, causing the soil to become granular and dry, degrading the quality of soil and disturbing plant roots.
In areas heavily infested with jumping worms, native plants, soil invertebrates, salamanders, birds and other animals may decline. Invasive worms can also help facilitate the spread of invasive plant species by disturbing the soil, which invasive plant species are quick to establish on. Additionally, when the soil organic matter is removed, bare soil is more prone to erosion, compaction and increased runoff. Even mulch and woodchips can’t withstand the appetite of jumping worms. Rapidly disappearing garden mulch is another indication that jumping worms are present in soils.
Not only do jumping worms feed more voraciously and impact soil structure more than other earthworms, they also grow twice as fast, reproduce more quickly, and infest soils at high densities. Jumping worms reproduce asexually, so it only takes a single worm to establish a new population. You will likely begin noticing the signs of, or seeing jumping worms, beginning in mid-June. Adults die prior to winter, but their young survive in cocoons and hatch in the spring. Cocoons are very small and dirt colored, nearly impossible to spot and can be spread easily in potted plants, tire treads, hiking boots, mulch, compost, potted nursery and garden plants, on landscaping equipment, and even in plant clumps we dig up and share with our friends and family.
Currently, there is no effective management option for Asian jumping worm infestations, so preventing their spread is critical. Without human assistance, jumping worms naturally expand their range very slowly, so it is very important that we aren’t moving them around. Here are some ways you can prevent the spread of jumping worms:
When acquiring soil, mulch, and compost ask if there is a weed-free/heat-treated option
Purchase bareroot trees and shrubs when available to avoid bringing in outside soil
When purchasing potted plants, inspect for signs of jumping worms such as granular soils or the worms themselves
Use caution when transplanting plants — keep in mind that eggs will be very difficult or impossible to identify.
Jumping worms are occasionally sold as fishing bait or for use in vermicomposting — do not buy jumping worms for bait or composting purposes.
Clean soil and debris from vehicles, equipment, personal gear, and boots before moving to and from a work or recreational sites.
Professional gardeners and landscapers should clean soil, compost, mulch, and debris from personal gear, equipment, and vehicles when moving from site to site.
Consider composting your leaves on your property instead of having them transported to another site for mulching, composting, or disposal.
For additional information or to report sightings of Asian jumping worms, contact CCE Yates Natural Resources Educator, Laura Bailey at email@example.com or (315) 536-5123 ext. 4127.