Stuck to their principled position against invasive species
By
Bonnie Phillips / ecoRI News staff
An
infestation of jumping worms, also known as snake worms, has forced the Rhode
Island Wild Plant Society to cancel its August native plant sale.
Pat
Foley, president of RIWPS, wrote in an email, “We have decided
to cancel our upcoming native plant sale. Based on conversations I had
this week with the volunteers planning the sale, we learned that invasive
‘jumping worms’ were discovered in some of the plant trays we were readying for
the sale.”
Even
though the invasive worms look
similar to the region’s more common earthworm, their behavior easily identifies
them. They slither through the grass like snakes and jump away if they are
disturbed. In their native Korea and Japan, they are called Asian jumping
worms.
“That
jumping is how they get away from predators,” said worm expert Josef Gorres, an
associate professor of plant and soil science at the University of Vermont who
formerly taught at the University of Rhode Island. “It scares them.”
RIWPS volunteers quickly began to triage the plants and “made the sad decision to dispose of those affected by the worms. However, without further work to ‘bare root’ the more than 1,000 plants intended for the sale and replanting them in clean pots and soil, we cannot feel confident we have adequately mitigated the infection,” Foley wrote.
The
Aug. 24 date is too close to effectively complete the remediation work and give
the plants time to recover, according to Foley. The sale was scheduled to be
held at the Pawtuxet Village Farmer’s Market.
“I
have made the very difficult decision that it is more prudent for us to cancel
the August sale rather than risk spreading the infestation to the gardens of
our members, friends and customers,” Foley said.
He
said the society is trying to reach as many prospective attendees as possible
about the cancellation.
“We
will take some critical lessons from this experience and continue to work
together to meet our mission of getting more native plants into Rhode Island
soil, while seeking to protect against jumping worms and other pests,” Foley
added.
Jumping
worms have probably been in the United States for more than 50 years. The story
told about their arrival involves a shipment of cherry trees from Japan that
was sent to Washington, D.C., and the worms were in the soil around the tree
roots. Whether that’s true, Gorres isn’t sure, but he believes the worms have
probably been in Rhode Island for a decade or more. Residents are just now
beginning to notice them.
A
survey of URI master gardeners conducted by Gorres in 2015 found snake worms in
Slater Park in Pawtucket and in gardens and mulch piles in Barrington,
Jamestown, North Kingstown, South Kingstown, and Richmond. The worms are common
at URI’s East Farm, where master gardeners maintain several gardens and
greenhouses, and they have been reported at other scattered locations around
the state as well.
Nan
Quinlan, who coordinates the master gardeners’ vegetable demonstration garden
at East Farm in Kingston, said the worms may have arrived there in deliveries
of mulch, soil, or potted plants, or even on the tires and fenders of cars and
trucks.
“There
are so many possibilities here that I strongly hesitate to blame any one
source,” she said. “What makes the most sense is that the Asian worms were
already present in the soil at East Farm for a long time and found their way to
areas like mulch piles and the compost pile we built and maintain inside the
garden.”
Quinlan’s
speculation that they may have come from deliveries of soil or potted plants
aligns with Gorres’ understanding that they are commonly transported in plant
material via the horticulture and nursery industry.
“Folks
in horticulture should worry because the worms can negatively affect their
stock of plants,” Gorres said. “The castings the worms produce are very
granular, very loose, so if anything tries to grow in the castings, the roots
will have a hard time getting a foothold. Plants need something more stable to
hold onto. It makes the plant wilt and look like they’re experiencing drought
symptoms.”
To
reduce the likelihood of the spread of the worms, Gorres suggested that
consumers ask vendors selling plants, mulch, or soil whether the worms have
been found in their products.
“They’ll
probably say they haven’t been, but if they’re truthful they may say it’s the
new normal, which it may be,” he said.
Gorres
is studying several varieties of insect-killing fungi that may control the
worms.
