Beware of … Jumping Worms?

There is a new pest in Illinois. Will you find it in your community garden? We look for earthworms in our gardens as a good sign. Worms help increase the amount of air and water that gets into the soil, and they leave behind castings that are a valuable type of fertilizer. That is rapidly changing; a new invasive and damaging pest may be in your gardens.

A local landscape designer described the devastation she has encountered in containers with this detrimental pest this way: “Generally, at the end of the growing season when I remove plants from containers, the roots are woven thickly together making each plant hard to remove. This year, plants easily pulled out of my containers with no soil attached to the roots.” The infestation she found causes the soil to deteriorate to something akin to loose coffee grounds. As the worms fed on the organic matter in the containers, the plant roots no longer had anything to hold onto! 

Jumping worms, (Amynthas spp.) were first identified in our region in 2015 in northern Illinois. These worms are native to East Asia, and they also have been called crazy worms, jumping worms, and snake worms because the worm thrashes wildly when handled or disturbed, and it can shed its tail in defense. The landscape designer we spoke with found these worms in Ravenswood Manor both in the ground and in containers, but she hasn’t seen them elsewhere yet.

Unlike red earthworms, these appear to be grey or brown. Jumping worms do not burrow far into soil – they live on the soil surface in debris and leaf litter. We are told to look for them in our gardens, in mulch, compost, potted plants and other suitable places. You will learn that the cocoons are nearly impossible to find; they are the size of mustard seeds, and although the cold kills adult worms, the cocoons protect them from cold.

CCGA community gardeners should start looking for them just as soon as the temperatures consistently rise above freezing. They become most active in June, but we’re not sure the temperatures this winter have been cold enough to kill the worms, and we know the cocoons are not killed by cold. (After the polar vortex at Halloween, our gardener saw plenty of them.) CCGA gardeners must be very, very careful and aware of this threat, and look for their presence in any potted plants that are purchased or shared and in any compost or mulch. Use only compost that you know has been heated to appropriate temperatures and duration following protocols for reducing pathogens. Test your own compost and garden soil with this mix: For every gallon of water mix with 1/3 cup of ground yellow mustard seed and pour slowly into the soil. This will drive any worms to the surface. If you have jumping worms be sure to capture them and to drown them in vinegar or solarize them in a plastic bag before discarding them in the trash. Then report it to your state’s Department of Natural Resources (DNR) so that they can track the spread, and absolutely avoid moving plants, compost or soil from your garden.

Please read through the information thoroughly on the websites given below. You’ll find Information for identifying the worms as well as recommendations on how to reduce their spread. At this time, there are no controls, organic or otherwise, to kill the worms or their cocoons. The WI DNR is doing some testing this coming year and we hope that their efforts will result in an organic method to rid our gardens of this terrible new pest.

For further reading:
https://ipm.illinois.edu/first_detector/Jumping_Worm_Handout.pdf
https://dnr.wi.gov/topic/invasives/fact/jumpingworm/index.html

Photo of adult jumping worms courtesy of UW Aboretum.