‘Scary’ invasive and destructive worms are in CT, ruining soil and gardens. What you need to know.

These jumping worms are in Connecticut, turn topsoil into grape nuts and are very destructive, experts say.

They are known as crazy snake worms, for good reason.

Asian jumping worms can grow up to 8 inches long and they will thrash you with their tails if you pick them up. 

They can climb up two-story buildings.

The main problem with them is they will turn your topsoil into the consistency of grape nuts cereal and loosen the soil around shallow-rooted maples.

“They’re like earthworms on steroids,” said Gale Ridge, associate scientist at the Connecticut Agricultural Experiment Station in New Haven.

“They have a high hydrostatic water content, so they feel like snakes and sometimes they’re called crazy snake worms,” she said.

“And they whip, they whip, they thrash when picked up or being threatened, and they can cover the ground very quickly,” Ridge said. “They’re very fast. They’re very good at climbing. They can climb up a building.”

Unlike European earthworms, which like jumping worms are invasive, jumping worms are bicolored. “Their top surface is dark, the underbelly is light colored and then they have a milky white collar that is flush with the body,” Ridge said.

Also, unlike earthworms, which flatten their tails to push themselves forward, “these move snake-like,” she said.

As they quickly move through the top organic layer of soil, “they turn it into this black granola grape nuts cereal-type consistency,” Ridge said.

“It is actually fireproof,” she said. “Fire goes over the top of it. Any worms that are in there are well protected and also protected against cold snaps,” such as one that hit the state in May 2023 that devastated the state’s fruit crops.

“Also because it’s loose, it’s more able to be washed away by the rain, so you end up getting a loss of topsoil,” Ridge said. “Native shallow-rooted plants can’t germinate in it. So things like the sugar maple, those seeds can’t establish, and so they could be a serious threat to the sugar maple industry.”

There are three species of the worms, which live just one year, but have an unusual way of reproducing.

“They are basically parthenogenic, so they don’t need males to produce a sizable population,” Ridge said. “They have the advantage of being annuals. Most important, earthworms are multi-annual, so they can live three, four years whereas this one only lives one year.”

Jumping worms create cocoons with one or two eggs in each and can produce 100 of these during their one year of life, Ridge said.

“These cocoons are the wet overwintering stage, and they can desiccate,” she said. “They can dry out in freezing conditions and so the cells are protected against bursting, and also in severe drought.”

Ridge said the worms engage in “cocoon banking.”

“Not all the cocoons will hatch the following spring. Some will just sit it out for a year later or a year later after that,” she said. “Not all are committed the following year. So if there is any harm to the population … they may pass through this event unscathed. So the following year, a young worm will then hatch.”

“I have them in my yard and they’re very destructive, and there really is not anything commercially available that you can use to make them go away, unfortunately,” said Dawn Pettinelli, associate extension educator at the University of Connecticut’s Department of Plant Science and Landscape Architecture.

Pettinelli said there are no native worms in New England’s soils.

“The glacier that came through here like 15-16,000 years ago had wiped out all the native worms, so we have no native forms in Connecticut, or in New England,” she said.

“When the trees and shrubs came back and they recolonized the landscape, they had formed a mutually beneficial or symbiotic relationships with microbial fungal organisms to all of our forested trees,” she said. “They all have extensive fungal networks with these micro-risal funguses, which are beneficial for them.”

Pettinelli said earthworms also damage the topsoil “but not to the same extent. They’re not as active and they aren’t as plentiful. They can damage the soil, but they do it to a much lesser extent.”

The Asian jumping worms were first introduced to this country in 1948 to feed Australian platypuses at the Bronx Zoo, Ridge said. After Superstorm Sandy in 2012, when 15,000 trees fell and were chipped and sold as mulch, the worms spread outside the city. 

There’s no really effective way to get rid of the jumping worms, Pettinelli said.

“If you can collect them or throw them out on the road or chop them into a million pieces or anything you can do to reduce the population would probably be helpful, but it’s really not going to solve the problem,” she said.

“I think it just makes the gardener feel better that you’re trying to do something,” she said. “I don’t know that you could get out there and collect enough and put them in buckets with detergent or something and kill them that you’d really make a big huge difference in the population. But the most important thing is don’t spread them.”

Ridge said some birds, salamanders, weasels, snakes, toads, pigs and raccoons will feed on the worms, but don’t make much difference.

However, Ridge said, “in the last couple of years, I have been getting calls from a citizen saying there’s this very odd-looking worm going across my driveway, and it has a head. It’s the hammerhead worm. It is actually a predator of the Asian jumping worm. It had been accidentally introduced decades ago, but populations never thrived.”

She said now that there are more jumping worms, “I wouldn’t be surprised if towards the end of the summer I’m going to get many more calls of these hammerheads, because once they’ve got the food source that they’ve evolved with available for them, then they’re going to become much more reproductive and much more successful and they’re going to go after it.”

Ridge suggested rototilling gardens in the first two weeks of May, when the young worms are hatching. Also, put down plywood, then pick the worms up from under the plywood and put them into a bucket of soapy water.

“Drown them, but do not dispose of them in the garden thinking you’re done,” she said. “If there are any cocoons that are about to be shed by the adult female, those cocoons will have survived that ordeal. So you need to dispose of them in the trash.”

Also, heat all mulch material to 105 degrees, don’t bring soil in with potted plants and check fishing bait to make sure there are no jumping worms mixed in with earthworms. Don’t dump your bait into the water, Ridge said.

The jumping worms are “just plain scary,” Pettinelli said. “They startle people when you’re doing a little bit of digging and all of a sudden it literally leaps out of the soil. … And then if you go to grab it, it sheds its tail, so you have its tail in your hand. And meanwhile the worm’s scurrying away.” 

Ed Stannard can be reached at estannard@courant.com.