Jumping worms — a new issue for Minnesota gardeners
Two common gardening practices spread jumping worms and their tiny egg cocoons. If you get a plant dug from a friend’s or neighbor’s garden or from a garden club’s plant swap and it still has any soil on its roots, you may be introducing the worms into your garden soil if its home soil has an infestation. If you use wood mulch or wood chips around your plants, the worms and eggs can live in that. As far as we know now, only heat of about 90° kills the worms and 115° kills the cocoons. Researchers believe the worms are killed by our winters, but the egg cocoons survive in the top two inches of soil to hatch the next year.
So, what about plants purchased from nurseries and garden centers and particularly the Friends School Plant Sale?
All of the growers for the Friends School Plant Sale are certified by the Minnesota Nursery and Landscape Association (or their own state's equivalent) and therefore use soil-free potting mixes, rather than soil from the ground.
Even before the jumping worm problem, MNLA members have been greatly concerned about not spreading plant diseases through potting soil, tools, plant material, etc. Their businesses depend on having their practices and plants inspected. We have paperwork from our growers stating that they are inspected by the Minnesota Department of Agriculture each year.
What can you do?
Prevention is the only possibility right now. Researchers at the University of Minnesota are working to find possible treatments, but it's not known if there will be one, or whether it will be acceptable for use by many gardeners even if they do.
Some Minnesota-specific links on this problem to learn more about it:
- The Jumping Worms Project, from the researchers at the U of M. Includes photos for differentiating jumping worms from other earthworms.
- The DNR jumping worm page
- Minnesota Invasive Terrestrial Plants and Pests Center (also at the U of M) (has multiple news story links)
- U of M Exension page on jumping worms
- EDDmapS - Invasive Species Mapping Made Easy for finding and tracking (you need to set up an account to report through the map), or report suspected worms directly to the DNR: Laura.Vanriper@state.mn.us
We will add more information here if we find out anything that is useful.