According to the maine.gov website, an invasive and destructive species of Amynthas worm, commonly called jumping worms (JW), has been found in 13 of Maine’s 16 counties, including Cumberland, since 2021. Two populations were discovered in Augusta (one at the Viles Arboretum) and two populations were found in Portland. They have also been found in a rhododendron garden at the Coastal Maine Botanical Gardens in Boothbay (https://bangordailynews.com/2018/01/06/homestead/crazy-worms-may-be-wiggling-to-a-garden-near-you/).
Jumping worms are smaller than night crawlers and earth worms, typically measuring about three to five inches in length. They have a distinctive whitish collar-like band (clitellum) around their bodies and are known for their thrashing, snake-like movement when disturbed. Their skin is smooth and rubbery, rather than slimy.
These worms are annuals with a life span of one year. Juveniles appear May into June and can produce two hatches per season. They are very small at this stage (a few inches) and have no white band yet, making them hard to identify.
Jumping worms live in the top three inches of soil and have a huge appetite. Gardeners should be on the lookout, as these worms can ruin the soil in our gardens and harm plant roots, leaving soil that resembles coffee grounds. They are a threat to forest soils, as well.
It is illegal to import these worms. The worms now found in Maine were brought here through the soil of nursery plants, in compost or in the crevices of hiking boots and tires. It is also illegal to sell them as bait.
For small infestations, hand removal followed by placement in soapy water can be effective. For easier identification, it’s best to wait until July or August after the worms have developed their characteristic white band. Although they die off each winter, they leave very small soil-colored cocoons, which are difficult to see. To make matters worse, they reproduce without mating.
There is no pesticide in current use to destroy them. To keep them in check, mix 1/3 cup of ground mustard with a gallon of water and pour it directly on the soil. This will bring them to the top to be scooped up; put in tightly sealed plastic bags and leave in the hot sun to destroy.
Solarization during the peak of summer heat is one of the most effective eradication methods. Spread a layer of infested soil (6 to 8 inches deep) on a sheet of black plastic, leaving an ample amount of uncovered plastic around the edges. Cover with a second layer of plastic and seal the edges to prevent escape. Leave in direct sun so the temperature exceeds 104 degrees for two to three consecutive days.