You’ve likely been told that earthworms are beneficial for the soil - they help with aeration and drainage, increase nutrient cycling, make nutrients more available to plants, and help create a healthy, sturdy soil. And that’s all true - usually.
Although there are some earthworms that are native to North America, it’s likely that the earthworms you’re familiar with are non-native species brought to the continent in the 18th and 19th centuries with imported plant material or, more recently, for fishing bait or composting. But there is one particular earthworm that is wreaking havoc on lawns, gardens, and forests: jumping worms.
Jumping worms, also commonly known as crazy worms or snake worms, are actually a group of non-native Amynthas species. Their name may be fun, but the damage they cause is anything but – these worms are voracious eaters, and can tear through the organic matter in your garden, lawn, or surrounding forests quicker than most other earthworms.
Jumping worms strip the soil of nutrients and organic matter, and destroy soil structure. Plants can be damaged, starved of nutrients, or left unstable in the structureless soil. This can have a particularly detrimental effect on native plants, and can even affect wildlife, by reducing vegetative cover necessary for protection and nesting.
To make things even worse, jumping worms are very fast growing and can actually reproduce without a mate. This means populations can skyrocket quickly after these jumpers worm their way into a landscape.
Unlike most earthworms, jumping worms can be easily identified by external features. Look for:
Jumping worms also have characteristic poo – their “casts” look like dried coffee grounds. The best way to identify them, though, is to handle them! As their name implies, jumping worms will thrash wildly (like, well, a snake) when touched – so wildly that they may even break off their tail in an effort to get away.
Earthworms don’t get a lot of press, so we aren’t entirely sure where all these worms have expanded to. There have been reports of jumping worms across the northeast, southeast, and midwestern US, but their range may expand beyond those regions.
These earthworms live close to the soil surface, and thrive in forests, gardens, parks, or lawns – really, anywhere that has organic matter in the soil for them to feed on and moisture to keep them from drying out. They can enter the landscape through compost, mulch, or soil infested with live worms or cocoons.
Because jumping worm populations can grow so rapidly, preventing these earthworms and their cocoons from entering the landscape is extremely important. Plus, there are no pesticides labeled for use against earthworms, so prevention is really the only viable solution to stop these worms from jumping from place to place.
Here are some tips for preventing the spread of jumping worms:
Check products before you buy: check compost, mulch, sod, soil, and potted plants for unusually active, jumpy worms or small yellow to brown lemon or teardrop shaped earthworm cocoons – if present, do not purchase
Clean tools between sites: clean soil off of gardening tools, vehicles, shoes, and equipment between sites to prevent the spread of jumping worms or cocoons
Read the label: Never buy any earthworms for fishing bait, garden use, or vermicomposting if they’re labeled as:
Properly dispose of fishing bait: just to be safe, never dump unused bait in the river, pond, forest, or landscape – take it home and throw it in the trash
Monitor your yard: keep an eye on the lawn, garden, and wooded edges for jumping worms – if you see one, throw it in the garbage
We know we’ve opened a can of worms here – it’s easy to let jumping worms loose, but very difficult to eradicate from the areas they’ve inhabited. If you do find jumping worms in your neighborhood or backyard, the best thing you can do is follow the steps above and contact your local extension office or a nearby university’s Integrated Pest Management team to report a sighting and request more information.