WORM WOES

August, it's that time of year. Invasive jumping worms (IJW)are grown up, plentiful, and faster than ever.  I have attended lectures hoping to hear of a magical solution but to date, none has arisen.

Stages of woe
1. Early spring (soil temps around 50 degrees).
​Tiny jumping worms hatch from cocoon encased eggs. How good is your eyesight? Those cocoons are 2-3 mm in diameter. The worms are also very small and easy to overlook as they blend in well with the soil and small twigs. The clitellum will be very faint. 

Photo by Marie Johnston, UW-Madison Arboretum

Newly hatched jumping worm. Photo by Marie Johnston, UW-Madison Arboretum

2. Late spring/early summer
IJW eat. Much like the very hungry caterpillar, they devour everything and will leave the soil devoid of nutrients and the ability to retain water.  Worms are smallish and not as squirmy during this stage; don't assume the worms you see aren't IJW.  (I KILL THEM ALL since earthworms aren't native either and do have negative effects on the ecosystem. Added bonus - they aren't reproducing at this time. See the video below, My Forest Has Worms.)

IJW in different stages

not fully developed

Clitellum is developed and fully encircles the body.

A bucket full of collected IJW.

These worms were collected in late August. Clicking on photos will open them up in a separate window.

3. Late summer 
Mature IJW reproduce. They are parthenogenic which means they can reproduce without a mate. It is not currently known how many each adult can lay but in laboratory settings, up to 30 cocoons with 2 eggs each have been observed. (UMASS). 

Mid-to-late summer worm castings become more apparent both in gardens (left) and the woods (right). The soil will be really loose and does not retain water.

4. HARD FREEZE (used to be in the fall but weather is unpredictable)
Adult worms die. 

5. Winter
Cocoons wait until spring temperatures reach 50 degrees and will reach maturity in 60-90 days

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Fact Sheet for Homeowners
Connecticut Ag Experimental Station IJW Fact Sheet

Straight from the scientists:
Video: Invasive Earthworms (Jumping Worms) Dr Josef Gorres
Video: Invasive Jumping Worms in Field and Forest Dr. Annise Dobson
Video: My Forest has Worms

Discussion
Facebook Group: Invasive Jumping Worms: Observation and Discussion Group

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HOW DO I GET RID OF THEM?
You will read or hear that a mustard pour, boiling/soapy water, and/or tea tree seed meal will kill the worms. Mustard pours do not, they irritate them and bring them to the surface. However, all of the above methods do have ecological consequences particularly for soft-bodied creatures like our native toads and salamanders. Tea tree seed has not been approved for this application but research is being done on its ecological impact. 

Others have said that their chickens and other birds will eat them and while this is somewhat true, IJW bioaccumulate heavy metals and toxins which impacts bird health. You can have your soil tested for toxins if you want to feed them to birds but it isn't recommended. 

Current best practices include:
Hand-picking and dropping them into a bucket of soapy/vinegar water and disposing once they are dead. (I wait a day or two just to be sure then dump them in one small area away from my gardens.) They do emit an awful odor if left too long. I carry a baggie with me while hiking and will collect the worms when I find them. I'll dispose of later - either by drowning them in a bucket or leaving the bag in the sun. 

Solarizing the soil. Using CLEAR plastic to create a greenhouse effect, you can kill the eggs before they start to hatch by bringing the soil temperature up to 104 for three days (does not have to be consecutive). You want the soil to be heated to a depth of at least 4".  

DON'T FEED THEM. Forget the mulch and add more aggressive native plants. Most prairie/meadow plants can tolerate the conditions. If you do buy mulch, soil, or compost make sure that they are free of IJW (really difficult when the season starts) but you can ask if the materials have been solarized and what they have done to prevent infestation.

BE WARY OF PLANT SALES Again, at the beginning of the season it is really difficult to know whether a pot has IJW or not. You can look for the castings. You could pull the plant out of the pot to see if there are tunnels created by IJW.

Buy Bare Root Plants. It's mostly shrubs and trees that are sold bare root (without soil). If you do buy potted plants, bring them home, knock off all the soil(into a bag), rinse the roots. Solarize the bag of soil, then strain the water for solids and dispose in the trash.

CLEAN your tools, equipment and shoes since cocoons could be present in the debris and could be transferred to other places.

Report them
There are many apps for you to use to report sightings of invasive species: IMapInvasives, EDD Maps, and iNaturalist  Contributions help scientists understand the scope of the problem and develop management strategies.