It was a typical April. Rising temperatures and alternating rainy and sunny days have yielded green, growing lawns; budding trees and shrubs and many plants poking their heads out of the ground. Just as we are eagerly getting outside and playing in the dirt we are being warned about a new pest surfacing in Minnesota that can have an adverse effect in our forests and urban landscapes.
Jumping worms, Amynthus agestis, are the latest threat to Minnesota plants. Native to East Asia, they were found in Wisconsin in 2013 and several years back in the main garden in Loring Park where it is believed they destroyed several plants. They were also reported in Minneapolis gardens that same summer.
The threat from jumping worms, also commonly referred to as crazy worms, Alabama jump worms or snake worms, is that they change the soil surface by disrupting the natural decomposition of the leaf litter. They turn good soil into grainy dry worm castings which can look like dry coffee grounds. In the forests they allow the spread of invasive plants by destroying the leaf cover that supports slower growing native plants. In urban areas they are harmful to turf and ornamental plantings.
Because they are able to reproduce on their own, jumping worms can reproduce and spread fast. Those found in Minnesota in years past apparently died over the winter, but with a mild winter like we had this year, and which will probably be more of the norm in the future, there is no way to know if they will be able to over-winter in the future. So with that unpredictability it will be up to us to stop the spread of the jumping worms.
The first step in our fight is to learn to recognize the jumping worm, which is easily identified by its looks and behavior. The jumping worm is 1.5 to 8 inches long and brown to grayish black in color. While at first glance it may appear to be an ordinary earthworm it has notable differences. Unlike an earthworm it has a rigid body that does not produce slime. Most notably it has a cloudy white, smooth clitellum (ring on the body) which encircles the whole body near the head. Other earthworms have a raised wrinkly clitellum. It lives in leaf litter and can be found in flower beds, mulch, compost, log piles and other places where it is shady and moist. When touched or threated it behaves more like a snake, slithering and trashing wildly – hence the names ‘snake worm’ or ‘crazy worm.’ Sometimes they may even shed their tail in defense.
To help prevent the spread of jumping worms watch for them in leaf litter, mulch and compost. Look for the unusual soil texture of jumping worm castings in your garden beds. Only purchase, use and plant landscape and gardening materials that are free of jumping worms. Only purchase and use compost that has been heated to appropriate temperatures and duration to make it free of pathogens. Destroy any jumping worms you find and do not use them for bait – they can live underwater for up to three weeks and once they wash ashore they can begin new populations around fishing lakes.