Your Questions about Asian Jumping Worms

Posted on Thursday, June 30th, 2022

Written by GTI Admin

left: two worms in the palm of a hand. right: a worm crawling in grass
There are two major species of Asian jumping worm, Amynthas agrestis and Amynthas tokioensis

Are Asian Jumping Worms invading Ontario?

Dr. Paige Boyle, who studies earthworm ecology, says, "I'm not entirely sure whether jumping worms have made it to Ontario, but I wouldn't be surprised if they have. I know they've spread as far north as Minnesota and Great Lakes region and in the northeast here in the states, so if you don't have them yet, it is probably just a matter of time! "

According to a recent blog, these worms were reported in the Greater Toronto Area in August of 2021, which were then confirmed with the expertise of Dr. John W. Reynolds from the Oligochaetology Laboratory in Kitchener, ON. 

What are Asian Jumping Worms?

Native to East Asia, jumping worms were first reported in Wisconsin in 2013. Like all worms, jumping worms feed on organic matter such as leaf litter and decomposing plant material. When populations are high, worms can deprive plants, fungi, and bacteria of the organic matter needed for growth and survival. One concern about jumping worms is that they are parthenogenetic, meaning they produce eggs without the need for a mate, so just one worm can start a new population which could result in an epidemic.

Jumping worms specifically create very grainy-looking and hard little pellets when they excrete. The digested soil resembles large coffee grounds, and can have poor structure for plants to grow in. They can cause damage in lawns by eating through the organic matter and roots quickly, and destroying soil structure. Jumping worms resemble regular earthworms (which are also not native to North America) but there are some important differences. Unlike other earthworms, they don’t produce slime and are more gray or brown in color than pink. Their clitellum (the band of lighter-colored tissue near the head) is smooth and not raised and whitish, not pink.

Jumping worms get their name from their behaviour—when handled, they thrash violently, may jump into the air or shed their tails like a newt. The adults die in winter, but the larvae overwinter as microscopic cocoons in the soil and leaf litter (so you might not see them in the spring). After hatching in late June, each worm begins reproducing; their life cycle lasts 60 days, so we can have two generations easily each year. 

jumping worm (left) has a white collar around the next, nightcrawler worms (right) have a pinkish collar

Should we worry about our lawns?

Research conducted at Colby College in 2019 titled "Asian jumping worm impacts on physical and biological characteristics of turfgrass ecosystems" (read it here) was unable to confirm that this species of worm negatively impacted the enzyme activity or organic mater compared to samples without added worms. However, this study was limited by time (the experiment was conducted within only 124 days), and it was difficult to prevent worms from contaminating the control "no worm" treatment. The conclusion from this study on wether this species is more damaging was: "it depends on the ecosystem composition".

It is important to note that the Lumbricus species (common earthworms and nightcrawlers) were introduced to North America in the 17th century. There is some data to suggest that these worms have negatively impacted the soil ecosystem and nutrient exchange in North American forests in the past two decades, but this is likely more of an issue in forests than turf due to the worms' preferred diet of leaf litter. In the turf industry, worms can cause damage to golf course greens and professional playing fields by leaving "castings" on the turf surface when are then smeared into an undesirable mark when mowing. In severe cases, it can be quite destructive. 

In short, our lawns are not likely at risk from Asian jumping worms. However, the establishment of this new and prolific worm on a low-mown surface like a golf or bowling green could result in something like this:

a golf green marred by several small mounds of black earthworm castings

How can we manage this?

Since no pesticides are currently labeled for earthworm control in turf, prevention is key. They are likely moving into home landscapes through mulch, compost, sod, soil, and/or potted plants, so check your purchased materials for worms or cocoons to prevent the spread.

Other tips from Dr. Boyle:

  • Don't buy earthworms for fishing bait, garden use, or vermicomposting if they are labeled as jumping worms, snake worms, Alabama jumpers, crazy worms, crazy snake worms, or Amynthas.
  • Properly dispose of unused live fishing bait in the trash, never dump in the river, nature, or landscape.
  • If they do get into the yard, remove them by hand and dispose of them in the trash
  • Rinse your boots off when coming home from a hike to stop the spread from forests to urban landscapes

For more information, check out this video from the University of Maryland: 

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