Q: A friend of mine offered to bring me a load of compost from the Twin Cities. I’m concerned about the spread of jumping worms. Is it safe to accept compost from that region?

A: It’s great that you’re thinking about how to help prevent this pest from spreading.

Jumping worms (Amynthas spp.) are originally from Asia. They were first found in Minnesota in Loring Park in Minneapolis in 2006, and they’ve since been reported in other metro counties and southeastern Minnesota. It’s believed that their spread is caused by people moving gardening materials and bait.

Jumping worms get their name from their energetic wiggling. They are very destructive. They strip the topsoil of essential nutrients and alter the texture of the soil, promoting erosion and killing plants. They can damage lawns, ornamental plants, crops, fields and forests.

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It’s possible to transport them in soil, mulch or plants without realizing it. They resemble earthworms — and even if there are no worms present, their tiny cocoons may be hidden in soil or mulch.

Currently, there are no pesticides to combat jumping worms that have infested an area. Our best defense is to try to keep them from spreading. A few things we can do:

  • Don’t dump bait worms outdoors.
  • Clean your shoes after hiking.
  • Clean garden tools before taking them to a different location.
  • If you use worms for composting, make sure you know how to identify the species you ordered, and check your order when you receive it.
  • Buy mulch without earthworms, and don’t spread mulch that has earthworms in it.
  • Don’t transport soil or plants from other people’s yards and gardens. If a friend wants to give you a plant dug up from a yard or garden, be sure to wash all the soil off the roots before moving it. You should be safe purchasing plants from garden centers, which typically use sterilized growing medium.

Jumping worms can alter the texture of soil so that it resembles coffee grounds, making it more susceptible to erosion. (Photo courtesy Beth Solie and Doug Dirks)
Jumping worms can alter the texture of soil so that it resembles coffee grounds, making it more susceptible to erosion. (Photo courtesy Beth Solie and Doug Dirks)

You may or may not be safe moving compost. It depends on how hot the compost got. Minnesota law requires commercial composters to hold compost at temperatures over 131 degrees, which is hot enough to kill the cocoons of jumping worms. So if you’re getting the compost from a commercial composter that is following the law, you should be OK. Don’t transport compost from a home garden.

So far, jumping worms have not been reported in St. Louis County. If you think you have them in your garden, it’s important to report them. They are a bit hard to tell from the other earthworms found in our yards and gardens (which are also not native and came from Europe).

Jumping worms thrash around when touched. (Photo courtesy Beth Solie and Doug Dirks)
Jumping worms thrash around when touched. (Photo courtesy Beth Solie and Doug Dirks)

The most striking difference between jumping worms and other earthworms is the raised band near one end, called the clitellum. In European earthworms, the clitellum is more raised and swollen and doesn't always go completely around the worm. With jumping worms, the clitellum is cloudy-white to milky pink to gray, is barely raised, goes completely around its body and is closer to the end. Another helpful distinguishing characteristic is the way they act. When disturbed, they are extremely wiggly and can even “jump” out of containers.

There are three ways to report jumping worms:

1. From a smartphone, download the free app from the Great Lakes Early Detection Network (Great Lakes EDN) and use the app to make your report.

2. On your computer, visit EDDMapS Midwest and click on “report sightings.”

3. Email the Minnesota Department of Natural resources at laura.vanriper@state.mn.us.

You can also participate in a research project, helping scientists figure out whether there are jumping worms in our area, just by scouting your own yard. More information is available here: jwp.cfans.umn.edu/jumping-worms-project.

Written by U of M Extension Master Gardeners in St. Louis County. Send questions to features@duluthnews.com.