(upbeat music) - [Narrator] This quiet community garden in Salem looks normal enough at first glance, but hidden in the soil is a destructive invader.

And no, it's not the usual suspects, like aphids or slugs.

- [Kathy] Okay, I'll see if I can get 'em again.

- [Narrator] It's something you might not even suspect.

- [Kathy] Here's one.

You can see him right there.

- [Narrator] A worm.

But not just any worm.

- [Kathy] He's very wiggly.

- [Narrator] It's a jumping worm.

- [Kathy] That's his mouth.

They're just all over the place.

- [Narrator] They might look like the common nightcrawler, but these East Asian worms are far more destructive.

They completely alter the soil structure, causing a chain reaction that threatens the surrounding ecosystem.

- The Minnesota DNR is warning gardeners and anglers to be on the lookout for invasive jumping worms.

- An invasion species in California.

Jumping worms could impact Kansans.

- These invasive creatures can pack up big ecological punch.

- [Narrator] Since 2013, states like Wisconsin and Minnesota have been hit hard.

The worms, named after their trademark thrashing, are spreading into native forests, where they devour leaf litter and other organic material that native plants depend on to germinate and grow.

In some areas, the forest floor is being completely transformed.

In Oregon, the first jumping worm was spotted in Grants Pass in 2016.

Since then, they've been seen all over the Willamette Valley.

- Let's see if I can get him again.

I first noticed them in 2019.

I had gotten some leaf matter, and there were tons of worms in this leaf matter, and I was really excited 'cause I thought, you know, worms are great for the garden.

But within a year or two, I noticed that the topsoil was all pebbly.

And so at that time, I got a lot of information about how they're invasive and they can destroy your soil.

- This is all very dry.

- They call it, like, rough coffee grounds.

And if I try to firm it up and create a ribbon, I can't really create a structure out of it.

It just crumbles.

- [Narrator] When jumping worms are reported, OSU Extension staff like Sam Chan and Brooke Edmunds respond quickly.

Beyond tracking the worms, they teach gardeners how to stop them from spreading and how to grow plants in soil that's been drastically altered.

- [Sam] The worms consume the organic materials and they cast out these granules.

They don't really absorb moisture very well.

- Normal garden soil, water would percolate down through the soil structure.

- [Sam] The water is not even penetrating it underneath it.

- This can have major effects for plant growth, where the roots are not able to get that water.

The water might be running off.

Imagine if you're out in a forest or a wetland, that's gonna have major effects to that ecosystem.

- I think there are certain things that don't do as well, like beets, certain onions, things like that that have a shallower root.

I bring in new soil and compost in order to get things to grow.

- Jumping worms spread a couple different ways.

You know, anytime you walk through a garden, you get little bits of soil that cling to your boots and your shoes.

In that soil, you could have very small juvenile jumping worms, you could have the eggs or cocoons.

It could come in on compost, sharing plants, and get moved around in leaf litter as well.

We're continuing to see new reports.

Every year, folks are finding it in new places.

Definitely spreading.

- [Narrator] There are more than 50 species of earthworms in Oregon.

And to the untrained eye, telling jumping worms apart from the rest can be tricky.

Entomologist Josh Vlach knows what to look for and how to tell them apart.

- In terms of identifying them, they have a fairly large mouth for a worm.

You'll actually see them kind of, like, extending it out.

(bright music) And then in the middle here, we've got this clitellum.

It's a reproductive structure.

And in these, it's typically much paler than the rest of the body.

And it's very smooth, it's kind of in line with the body versus some of the European species that are actually kind of swollen looking.

- [Narrator] Probably the most obvious feature is their signature thrashing or jumping, which is the worms' defense mechanism.

- You can actually see this worm here, see how it's creeping?

One of the European ones kind of inching along by pulling its body.

And the Asian ones will, like, snake around.

So, I mean, just by movement, you could know.

Where they're being established in the Eastern US, like Minnesota, you get really dense layers of leaf litter on those forest floors.

And you introduce these guys, and they're really good at eating that material.

They stay on top, they'll eat it all until it's just bare earth.

- [Narrator] In the worms native habitats in East Asia, ecosystems have had millennia to adapt and to keep jumping worm populations in check.

Here in the Pacific Northwest, our forests aren't built to lose their leaf litter so fast, so the damage cascades.

- [Josh] There's whole communities of organisms that live in that leaf litter.

Those are essentially losing their entire habitat.

Even makes it more difficult for the trees to regerminate.

- [Narrator] Once the worms move in, they're nearly impossible to get rid of.

- They are somewhat sensitive to heat.

There's been things that have shown that, like some fires in the east have reduced their numbers.

There's also some information like using tarp, basically tarping the ground and getting the ground hot.

But they can go very deep.

And so you can maybe do some things to reduce their numbers, but I don't know of a good way to, like, eliminate them entirely.

- [Narrator] The worms aren't confined to the Willamette Valley.

A recent report in Northeast Oregon brought OSU Extension staff Amanda Woodlee and Karen Wagner out to investigate.

They've identified a small area next to this community garden shed.

- [Karen] All this soil looks definitely affected.

- [Amanda] Mm-hmm.

Oh, there he is.

- [Narrator] It's the first time jumping worms have been spotted this far east in the state.

- A lot of times when you disrupt the soil, they'll just pop up.

- [Narrator] One of the main threats is flat-out dominance.

They outcompete other species for food, eventually pushing the helpful worms out entirely.

- [Amanda] Every time we've been over here, we've not seen any beneficial worms.

We've only found ones that are either definitely jumping worm or suspect.

So that's alarming to me because there should be earthworms in a healthy soil.

- Mm-hmm.

Bad!

There we go.

- [Amanda] Another one bites the dust.

(upbeat music) - [Narrator] It's one thing to find jumping worms in community gardens, but it becomes a much bigger concern if the worms start spreading into farmlands and forests.

- On the east side of the country, their forests have been totally invaded and really decimated.

So, we don't know yet whether they would like our high dry ponderosa pine forests.

It could really wreak havoc.

(music) - [Narrator] Oregon hasn't been hit as hard as other states, but the worms are here, slipping quietly into nurseries, gardens, and even front lawns.

Finding them doesn't mean your plants are doomed, but it does mean paying closer attention to the soil under your feet.

For now, the best tool we have is awareness.

Spot them early, slow the spread, and give our forests and gardens a fighting chance.

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