|
For Immediate Release: Thursday, Aug. 2, 2018
Iowa State and Iowa
Department of Ag asking citizens to report other possible infestations
DES MOINES – Mile-a-minute
weed, an invasive weed from eastern Asia has been found for the first time in
Iowa. Prior to this, mile-a-minute weed was known to be in the mid-Atlantic
states, but only as far west as Indiana and Kentucky, and an outlier in Oregon.
A
concerned landowner in Marion County requested identification assistance with a
vine that was growing on the edge of a wooded area surrounding his well-kept
garden. Representatives from the Iowa Department of Agriculture and Land
Stewardship and Iowa State University Extension and Outreach visited the site. ISU
weed scientist, Bob Hartzler, and a field agronomist identified the plant as
mile-a-minute weed (Persicaria perfoliata).
It is unknown how widespread this invasive vine may be across
the state. Iowans who think they have an infestation are encouraged to contact
Bob Hartlzer at ISU at hartzler@iastate.edu or 515-294-1164, or Lane Kozel, deputy
weed commissioner for the Iowa Department of Agriculture and Land Stewardship, at Lane.Kozel@IowaAgriculture.gov or 515-725-1468 for assistance
with identification.
Mile-a-minute
weed is an invasive species in the Polygonaceae (smartweed) family. It is a herbaceous
annual vine that can grow up to 20 feet long; has light green, triangular
leaves; many sharp, downward curving spines on the stem, petiole and main leaf
veins; a saucer-shaped sheath (ochrea) that encircles the stem at the nodes;
and round, iridescent blue fruit about 0.25 inches in diameter borne mid-July
until frost.
“Although
this was my first encounter with mile-a-minute weed, it was easy to see why the
plant is considered a threat,” according to Bob Hartzler. “This infestation was
less than a quarter acre in size, but it was crowding out existing
vegetation. The weight of the plant was pulling down a stand of
miscanthus, a species known for establishing monocultures.”
Mile-a-minute
weed grows best in moist, sunny locations with an abundance of plant material
such as leaves, duff, or brush on the soil.
Seed can
be spread birds, rodents, and humans. Seeds can also move with water,
especially from infestations along a stream. Human-assisted movement can
deliver seeds to new sites with alarming speed. Movement of soil containing
seeds via potted plants or equipment with soil attached is common in infested
states.
There is
no easy method for eradicating invasive species, and mile-a-minute weed is no
different. It appears this infestation had been present for at least five
years, thus there will be a large seedbank present. Studies have
shown seed can survive for at least eight years, and management will take a
long-term commitment.
Herbicides
can be effective, but multiple applications will likely be necessary during the
growing season. Nonselective herbicides will damage other plants in the
area, opening the site up for invasion of other weeds or new flushes of
mile-a-minute weed. The plant has a small root system, so hand pulling is
a relatively easy (gloves are recommended due to the spines) and effective way
to remove plants.
The Forest Service has worked on the biocontrol of
mile-a-minute weed since 1996. Iowa officials are now investigating the
potential for using a weevil that is host-specific to the invasive vine. The weevil has been released in other states
since 2004, with success tied to weather conditions. “We are looking into the
details associated with possible weevil releases to help control mile-a-minute
weed,” said Kozel.
    ###
For more information, contact Dustin Vande Hoef, (515) 281-3375 or (515) 326-1616 (cell) or Dustin.VandeHoef@IowaAgriculture.gov
|
