Don't Jump for Jumping Worms
You've probably heard of them , but have you actually met one? Read on to find out!
There are over 1000 species of jumping worms worldwide. Sixteen species are recorded in North America. It might surprise you to find out that the first recorded jumping worm in North America was recorded in California in the 1900s. Since then, they have been spreading. They travel in soils and mulches, and in the roots of potted plants.
Jumping worms are a glossy grey or brown. Unlike 'good' earthworms, the clitellum (reproductive tissue) does not form a raised saddle. It is a smooth, pale ring encircling the worm (see image). They get their common name because of their defensive habit of thrashing about when disturbed. Their casings look like coffee grounds.
What's the big deal?
Jumping worms live in the same environmental niche as native invertebrates and insects. They reproduce quickly and crowd out native species.
The biggest problem with jumping worms, however, is that they live in the top 4-6" of duff (the organic matter, such as decaying leaves and branches), whereas most worms live deeper in the soil. By consuming the duff, jumping worms consume the nutrients seedlings depend upon to grow. In natural areas, this can result in fewer understory plants.
By consuming duff, jumping worms consume the nutrients seedlings depend upon to grow.
How do I know if I have jumping worms in my garden?
Try the Mustard Test.
It is not possible to mustard test an entire garden. Keep a look out for jumping worm droppings, which resemble coffee grounds. That's where you want to test.
Mix 1/3c of mustard powder with 4.5L of water. Mark off a 30cm square, and pour half the solution over it. Wait a few minutes, then pour the rest over the space. Any worms living in the soil will come to you, and you can identify the jumping worms either by the description above, or by picking them up to see how they behave. The mustard irritates the worms, but does not injure them, nor does it harm your plants.
On hot days, they will pop their little heads up and you can try to nab it. WARNING: if you grab one by the tail, it will drop its tail.
Jumping worms can be destroyed by bagging them and freezing them. Egg cocoons can be killed by solarizing: bring soil to 40C for three days.
Oh no! I have jumping worms!
Don't panic.
Report them at the following link: https://www.ontario.ca/page/invasive-species-ontario
Do not use them for bait, put them in your compost, put them in the green bin alive, or toss them over the neighbour's fence. Destroy them by freezing them.
Do not share compost, soil or mulch.
When dividing plants, rinse roots thoroughly with water and repot in brand new potting soil.
Don't dump soil and plants into wild places. Jumping worms can be harmful there, too.
No worms? Yay! How do I keep it that way?
Do not bring outside soil or mulch into your yard.
Make your own compost, mulch and potting soils.
Clean all tools, and make sure any landscape contractors working in your yard are doing the same.
New plants should be planted bare root, and any soil should be solarized or disposed off.
Sources/ further reading
When using the mustard powder, it's best to dissolve it in some HOT water first, then combine with the remaining water. Otherwise you will be stirring forever. Jumping worms can also be destroyed by pouring 70% alcohol on them, or solarize them in a clear plastic container.