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Don your gardening goggles, jumping worms are real

I recently heard about an invasive species called jumping worms. Is that yet another thing we have to worry about in Southern Oregon?

— Concerned Gardener

According to the Oregon State University Extension Service, jumping worms are for real, Concerned Gardener, and they’ve recently leapt into the consciousness of gardeners throughout the Pacific Northwest.

The first jumping worms — a species called Amynthas gracilis — was found in 2016 in Grants Pass, where it was passed along through compost, according to Sam Chan, Oregon State University Sea Grant Extension watershed health and aquatic invasive species specialist.

Another species — Amynthas agrestis — has landed in at least six counties, from Pendleton in the east and to the I-5 corridor down to Roseburg, OSU Extension says. Most likely they arrived as tiny cocoons in plants, soil, mulch and tire treads from the East Coast, where they do extensive damage to forests.

“Unlike beneficial earthworms and nightcrawlers that burrow deep in the soil, aerating and releasing nutrients as they go, jumping worms stay in the debris on top and eat two to three times the amount of leaf litter as the other worms,” said Chan, in a recent article posted by OSU Extension.

“Jumping worms, which are native to many parts of Asia, are easily identified by their violent thrashing, slithering and actual jumping in the air. They are smooth, glossy gray or brown and 1.5 to 8 inches long. ... Because they have very large mouths akin to mechanical excavators, jumping worms are able to grasp and consume large amounts.”

With their voracious appetite, they outcompete native worms and other mulch-chomping bugs, OSU says. Their propensity to eat all the litter creates bare soil, removing the mulch that helps cool the soil and conserve moisture.

Further, the castings — or fecal material — of most worms contain important microbes and nutrients that improve soil. With jumping worms, the opposite is true.

“What they are casting out doesn’t absorb moisture well, so you end up losing porosity, which affects the overall structure of the soil,” Chan says. “Initially wet and gummy, the castings quickly dry into hard granules that are difficult to re-wet, not the best medium for growing plants.”

Jumping worms have been outlawed in many states, but not all, and can still be found online for fishing, OSU says. Chan advises to be careful not to purchase jumping worms, also known as crazy worm, Asian jumping worm and snake worm, and to spread the word about their danger.

“Many people — even those who sell them — aren’t aware of their invasiveness,” he says.

“Jumping worms are probably here to stay,” Chan says. “We want to minimize their spread. You won’t want them to get established in your garden. I sure don’t want them in my garden.”

Send questions to “Since You Asked,” Mail Tribune Newsroom, P.O. Box 1108, Medford, OR 97501; or by email to youasked@rosebudmedia.com.