After hitchhiking a ride from Asia, jumping worms have been wiggling themselves across Oregon since 2016, said Sam Chan, an invasive species specialist at Oregon State University.

The Amynthas agrestis, known as the “jumping worm,” gets its name from erratic thrashing of its body. They range from 1.5 to 8 inches long and are a glossy brown or gray color with a milky white band 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,” said Chan.

Jumping worms thrive in climates with hot summers and cold winters, but in Oregon they are not as picky. Populations can be found along the Interstate 5 corridor in moist, warmer weather and sprinkled along Pendleton’s Interstate 84 section with its dry, warm climate. They are commonly found in home gardens and can live in nurseries.

However, there have been no reports of the worms in commercial greenhouses in Oregon.

Adult jumping worms create cocoons that are about the size of a grain of rice. The eggs hatch in April and May. The worms will grow into adults in the summer until they are ready to reproduce in August and September. In late fall to early winter, the adult jumping worms begin dying off due to the cold weather. The cycle picks up again in the spring.

The worms are extremely invasive, and are unintentionally spread, often by people in the agriculture industry.

Fishermen also buy them as bait, and they are used in compost bins.

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

Despite looking relatively harmless, jumping worms are detrimental to landscapes.

They live near the soil surface, unlike other earthworms, which inhabit the lower organic layer. This allows the jumping worms to devour the organic matter and leaf litter that plants depend on to grow and survive.

Unlike earthworms, they can burrow deep tunnels in the soil and release feces as they go. The castings resemble 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 the soil.

Another notable characteristic of the worm is its giant mouth, which opens like a mechanical excavator.

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

Minimizing spread

It is impossible to tell just how many jumping worms are in the state, said Chan. However, they occur at higher densities than other earthworms. 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 can repel the worms.

“The best way to minimize their spread right now is just be able to recognize them,” said Chan. 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,” said Chan.

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

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

Phone: 1-866-468-2337

Online: https://oregoninvasiveshotline.org