The hundreds of attendees at the recent excellent UMass Jumping Worm Conference said much about concern with newer invasive earthworms. Although our Northeast US earthworms, familiar to most gardeners, are not native to the region, the ‘crazy,’ ‘snake,’ or jumping worms – so-named for their violent movements when handled – appear to be spreading and are the ones causing alarm. At least three Asian species introduced to the US about 80 years ago, including Amythas agrestis, A.tokioensis, and Metaphire hilgendorfi (there are others), are involved; their activities near the soil surface deplete organic matter and can dramatically convert the top soil layer into a light, granular material some liken to coffee grounds. This can be difficult for establishing new plants and frustrates efforts to maintain a mulch layer. In turf, the castings are unwelcome for mowers and golfers. In forests their presence may be affecting regrowth of trees, shrubs and herbaceous plants and there’s evidence the worms can concentrate heavy metals that could be an issue for wildlife. I first encountered them at a public garden some years ago, noticing the mulch layer on pathways and in wooded sites was disappearing under a layer of worm castings. To avoid further spread some garden clubs have halted plant exchanges – there is some concern for possible spread through infested compost or potting media. There is no product currently registered in the US for control of earthworms; emphasis is placed upon prevention as established populations can be very difficult to nearly impossible to eliminate. Read more at the JWORM Working Group page (http://www.nyisri.org/research/jworm-2/), in the homeowner’s guide (https://ecommons.cornell.edu/handle/1813/103692), or in several other on-line resources (e.g., https://www.dnr.state.mn.us/invasives/terrestrialanimals/jumping-worm/index.html and https://ag.umass.edu/landscape/fact-sheets/jumpingcrazysnake-worms-amynthas-sp). (Photos show a mature jumping worm and handfuls of their castings.)
Dan GilreinEntomologist, Cornell Cooperative Extension of Suffolk County
Dan Gilrein is the Extension Entomologist with Cornell Cooperative Extension of Suffolk County at the Long Island Horticultural Research and Extension Center, Riverhead, NY since 1995 and previously served there as IPM Specialist with Cornell from 1987. In his current position he conducts applied research on control of arthropod pests in food crops and on ornamental plants, provides diagnostic services to the horticultural industries, and conducts educational programs and presentations for industry, government officials, civic groups and the public on pests and pest management.