Vol. XVI No. 1
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January / February 2022
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www.SoilandMulchProducerNews.com
Jumping Worm Threat to Mulch Still Without Merit
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ildfires. Earthquakes. Famine. Drought. As if life isn’t complicated enough with those and other challenges, along comes the latest concern: jumping worms. Jumping worms? Although the wriggly creatures have been around for decades in the United States, researchers are paying renewed attention to jumping worms (Amynthas spp.) as their population has exploded and spread and the effects they are having on the environment. Even the soil and mulch industry is monitoring the issue. Annise Dobson, a postdoctoral researcher at the Yale School of the Environment, describes the spread as “global worming.” “There are concerns about the effects these worms will have on forests and other natural areas as well as agricultural and landscaped areas,” notes the University of Illinois Extension in an invasive species alert. “Populations of jumping worms have the potential to change the soil structure, deplete available nutrients, damage plant roots, and alter water holding capacity of the soil.” “Asian jumping wor ms devour organic matter more rapidly than their European counterparts, stripping the forest of the layer critical for seedlings and wildflowers,” adds the Cornell Cooperative Extension. “Jumping worms grow twice as fast, reproduce more quickly, and can infest soils at high densities. In areas of heavy infestation, native plants, soil invertebrates, salamanders, birds, and other animals may
By P.J. Heller
decline. These invasive worms can severely damage the roots of plants in nurseries, gardens, forests, and turf. They, along with other invasive worms, can also help spread invasive plant species by disturbing the soil.” The worms change the texture of the soil, making it appear more like coffee grounds. Jumping worms, a type of earthworm native to East Asia, are also known under such names as snake worms, Alabama jumpers, crazy worms and Asian Amynthas worms. They are so named because the reddish-brown iridescent worms will thrash and jump when disturbed. In the US, they can be found in about two dozen states throughout the Southeast, the Eastern Seaboard, the mid-Atlantic, the Midwest and the Pacific Northwest. “People spread jumping wor ms throughout North America by moving potted plants, soil, compost, mulch and fishing bait,” according to the Minnesota Department of Natural Resources (MDNR). Jumping worms have no predators and any chemical treatments that would
kill them would also kill beneficial soil organisms as well, MDNR says. The general consensus among researchers seems to be that temperatures above 104 degrees Fahrenheit will kill them, although the amount of time required at that temperature may vary. “The temperature that seems to kill both worms and cocoons is 105F,” says Josef Gorres, associate professor in the Department of Plant and Soil Science at the University of Vermont. “However, even in a well-maintained windrow that reaches 160F, the worms migrate to the outer edge of the pile where it is cozily warm for them.” The Cornell Cooperative Extension advises that when purchasing bulk mulch or compost, “use a reputable producer that has heat-treated the material to a temperature of 130°F for at least three days to destroy the cocoons or purchase bagged mulch.” The Yale School of the Environment’s Dobson advises the public to be careful of where it buys its mulch, topsoil and compost. “Ensure it has been heat treated to 104 degrees for three days and hasn’t been sitting around where jumping worms are present,” she recommends. Robert C. LaGasse, executive director of the Mulch & Soil Council, says claims Continued on page 3