GRAND RAPIDS, Mich. (WOOD) — The jumping worm has made headlines in recent weeks. The invasive species, first found on American soil in the late 19th century, has been confirmed in 34 states and is slowly spreading, including in Michigan.
So what do we know about this pint-sized pest? And do farmers or gardeners need to be worried?
The invasive jumping worm was formerly known as the Asian jumping worm because they are native to Japan and the Korean peninsula, but the name was changed to avoid any negative or offensive connotations.
They go by several nicknames: jumping worms, crazy worms, snake worms, wood eel, Jersey wigglers or Georgia jumpers.
The worms have an annual life cycle. Adult worms will die following the first hard frost, while the next generation survives the winter in its cocoon. The worms will hatch once the soil temperature consistently stays above 50 degrees. It takes the worms about two months to fully mature.
Unlike your run-of-the-mill European earthworms, jumping worms typically thrash around. That’s where the jumping moniker comes into play. The worms writhe so much and so vigorously that they can throw themselves off the ground, up to 12 inches in the air.
Another key difference is the color and texture. Both earthworms and jumping worms have a band called a clitellum. On an earthworm, the clitellum sticks out more, is a reddish-brown color, and is closer to the middle of the body. In jumping worms, the clitellum is a milky white color that is flush with its skin and closer to its head. Adult jumping worms also have an iridescent sheen and are drier to the touch.
HOW DID THEY GET HERE?
Jumping worms were first discovered in America in the late 1800s, brought over from Japan in the root balls of decorative plants. But only in the last few decades have the worms been spotted in American forests.
Jumping worms are still largely spread by humans, occasionally hitching a ride on shoes or equipment. They can also be found in bagged soil or mulch. The Wisconsin Department of Natural Resources suggests making sure any mulch you buy has been heat treated for at least three days to kill off any worms or eggs.
Though it may seem like a win-win scenario to use jumping worms as fishing bait, experts recommend against it because they can easily hop out of a bait can and spread to a new environment.
WHY ARE THEY A THREAT?
A worm isn’t much of a predator, but it can still make an impact on its ecosystem.
Because the jumping worms thrash around so much, they are known to be voracious eaters. Jumping worms live in the top layer of soil, eating leaf litter and absorbing the nutrients on which other plants and insects rely.
With that insatiable appetite, jumping worms leave behind a granular waste that doesn’t retain water and makes the soil more likely to be washed away. Experts at Cornell University have also shown that the soil disruption caused by jumping worms also provides more opportunities for invasive plants to move into an ecosystem.
HOW BIG IS THE PROBLEM IN MICHIGAN?
Jumping worms were first confirmed in the wild in Michigan in 2008 by Professor Scott Tiegs in the Oakland University Biological Preserve. Officials with Michigan’s Department of Natural Resources speculate the worms have been here for longer and are widespread at this point.
Since there is no feasible way to treat all soil across the state, the DNR isn’t putting up much of a fight. Jumping worms are considered an invasive species but there is no active program to try and stop them.
DNR officials say it’s more up to farmers and gardeners to do their part and protect their own turf.
HOW TO GET RID OF JUMPING WORMS?
The good news is you don’t have to go digging up your garden to try and get rid of jumping worms. One popular and effective method is called a mustard pour.
A mustard pour involves mixing one-third of a cup of ground mustard seed with a gallon of water. Focus your pour on a few square feet at a time. Pour half the liquid into the ground, wait a few minutes and then pour the rest.
The mustard pour will not hurt your plants or the worms, but it will force the worms to the surface. Collect the jumping worms in a plastic bag, leave that bag in the sun for at least 10 minutes, then throw it away.