Watch out for weird worms

photo of invasive jumping worms, annotated to show segments from head

A slightly shorter version of this article was published in the May 2024 of North End Breezes, a community newspaper in Hamilton Ontario. 747 words © Beverley Wagar 2024 please email me for reprint permission.

Jumping worms arrived in southern Ontario at least a decade ago and, since 2019, they’ve been writhing and chomping through gardens and naturalized areas in Toronto, Burlington, Dundas, and Hamilton. Unlike the familiar wigglers and crawlers, these weird, invasive, snake-like worms in the genus Amynthas thrash wildly when disturbed. Despite being surface dwellers that die in the winter, they are formidable ecosystem engineers. Eating all available organic matter (mainly leaves and seeds but also wood mulch and peat) they transform the topmost soil layer into dry, granular castings that damage the soil’s chemistry, biology, and structure. Forests and gardens can no longer support seedlings, mychorrizal networks, and the soil food web. Understandably, gardeners are afraid.


Mature jumping worms can reach seven inches in length. Look for the telltale light-coloured band (clitellum) that completely encircles the worm near its head. Other features include: skin with an iridescent sheen; thrashing behaviour; and a snappy almost “muscular” feel when held between the fingers. It may shed its tail when threatened.

To enable a positive identification, take several good photos and report the observation to iNaturalist ( ) or EDDMapS Then kill the worm by dropping it into a tub of vinegar or isopropyl alcohol. Do not put jumping worms in the compost or throw them away.

Life Cycle

Jumping worm eggs overwinter in the soil. Hatching starts in late spring when temperatures are consistently above 10C. By about mid-June, worms are large enough to identify. About 60 days after hatching they begin depositing egg cases—researchers estimate about four per week. To check for their presence, poke the soil with something like a barbeque skewer or screwdriver. Disturbing the soil will bring them out of the duff where they are easy to grab.

Another way to bring them to the surface is with a slurry of dry mustard (information here: . The mustard will not harm the soil, your plants, or the worms.

There are no registered pesticides for jumping worm control. In the USA, there is ongoing research on biocontrols (Beauvaria bassiana for example) and saponin-based vermicides (such as tea seed meal from the oil of Camellia oleifera) but a commercially available control product is many years away. Predators can reduce worm populations but, on their own, are not effective for the kind of control that gardeners want. Potential predators include snakes, centipedes, moles, gophers, skunks, opposums, and racoons but we don’t know whether they will develop a taste for this new food source.

Heat is lethal to both both eggs and worms but more research is needed to clarify the required temperature and duration. Laboratory research (Johnston & Herrick 2019) has shown that 40C for three days is required, but the study’s author has stated, anecdotally, that five hours would probably be enough (video–beginning at 50 minutes). It is very difficult solarize (to 40C) infested soil in the garden, even on hot days in July.

Prevention is the best strategy to keep your garden safe from jumping worms

Reduce the risk

Jumping worms reproduce without mating so it only takes one worm, or egg, to start a new infestation. The tiny (1 to 2 mm) eggs can hitchhike in soil stuck to boots, tools, and tires. Both worms and eggs can arrive in bulk soil amendments such as woodchips and mulch as well as purchased plants.

Gardeners, often unaware that they have jumping worms, may donate “dug” plants to neighbourhood plant sales or swaps. Root-washing and re-potting dug plants can reduce, but not eliminate, the risk.

Here are some tips:

  • Do not share plants. Neither give nor take. Gardeners often are unaware that they have jumping worms.
  • Ask garden center staff about how they are dealing withjumping worms.
  • Use native plants. Most are better able to withstand infestations.
  • Grow your own plants from seed. Use sterile potting mix.
  • Before planting, wash off all soil or potting mix from roots.
  • Provide shoe covers for garden visitors.
  • Clean shoes and tools when leaving an infested area.

Spreading worms (or their eggs) is always a possibility, even when there are no visible signs of their presence. If we act as if every garden, trail, park, and conservation area is infested (and many ecologists predict this will happen over the next few decades) we can reduce the risk of bringing home jumping worms.

Resources and Further Reading

Resources on
Q&A from UMass extention (very comprehensive)
Adapting to Invasive Jumping Worms (article at PennState extention)