CORVALLIS — After hitchhiking a ride from Asia five years go, an unusual worm has been wiggling its way across Oregon, said Sam Chan, an invasive species specialist at Oregon State University.

The Amynthas agrestis, known as the “jumping worm,” gets its name from the erratic thrashing of its body. The worm ranges from 1.5 to 8 inches long and is glossy brown or gray with a milky white band wrapping around its middle.

“If you see this worm that looks like an earthworm that has an unusually snake-like movement, and it wiggles and it literally jumps off your hand, then it’s very likely that it’s a jumping worm,” Chan said.

Jumping worms thrive in climates with hot summers and cold winters, but in Oregon, they seem to be less picky. Populations can be found along the Interstate 5 corridor in Western Oregon and along Interstate 84 near Pendleton in Eastern Oregon.

They are commonly found in home gardens. There have been no reports of the worms in commercial greenhouses in Oregon, Chan said.

Adult jumping worms mold a protective encasement around eggs until April to May, when tiny jumping worms hatch as the weather heats up. The worms will feed and continue growing into adults in the summer until they are ready to reproduce in August and September. In late fall to early winter, the adults begin dying off due to the cold weather. The cycle picks up again in the spring.

The worms are extremely invasive to Oregon, and are unintentionally spread, often by people in the agriculture industry. Also known as “Alabama Jumpers” or “Crazy worms,” fishermen purchase them as bait, as they wiggle in the water for 15 to 30 minutes, attracting fish in the process. They also are used for home gardening and bin compost.

However, Chan said this is not recommended as it continues the spread of the population.

Despite seeming harmless, jumping worms can be detrimental to landscapes. The invasive species lives near the soil surface, unlike other earthworms, which inhabit the lower organic layer. This allows the jumping worm to devour the organic matter and leaf litter that plants depend on to grow and survive.

They also burrow deep tunnels in the soil and release feces as they go. The casting resembles cooked hamburger, said Chan. In their path, they leave behind loose soil with a texture similar to coffee grounds. The soil can no longer retain moisture and lacks nutrients.

Also, worm activity eliminates insulation around plants and allows heat to penetrate quickly into the soil.

Another notable characteristic of the worm is their giant mouths, which open like a mechanical excavator.

“It’s a little bit like that from the horror movie,” Chan said. The worms have insatiable appetites and can outcompete other native organisms.

It is hard to tell just how many jumping worms are in the state, Chan said. However, they occur at higher densities than other earthworms in Oregon. In one square yard of soil, thousands of jumping worms can be found.

Right now, there are no biological controls or certified pesticides that can be used to eradicate the jumping worm. Some early work looked into fertilizers containing saponin, which is plant-derived glucose that repels the worms.

“The best way to minimize their spread right now is just be able to recognize them,” Chan said. If detected in gardens or crops, he advised contacting the Oregon Invasives Hotline and submitting a photo for identification.

If there is a contained population in a landscape, jumping worms can be placed in plastic bags and exposed to the sun. This will generate a temperature of up to 160 degrees, “which is more than enough to be lethal to the worms,” Chan said.

To stall the spread when gardening or cultivating crops, tools and work gear such as boots should be cleaned, as their cocoons can stick to them and spread. Despite the vast population in Oregon, there still are opportunities to slow it from growing further.

“We still have a chance to keep them contained,” Chan said, “because they’re not everywhere.”

Phone: 1-866-468-2337

Online: https://oregoninvasiveshotline.org