Forest Health Technology Enterprise Team
http://www.fs.fed.us/foresthealth/technology
P R O V I D I N G T E C H N O L O G Y F O R F O R E S T H E A LT H P R O T E C T I O N
Mile-a-minute weed Biological Control
Mile-a-minute weed, Persicaria perfoliata (L.) H. Gross
(= Polygonum perfoliatum L.) (MAM) is an invasive,
annual vine in the family Polygonaceae. Widely distributed throughout eastern Asia, it was introduced
into York County, Pennsylvania from Japan in the
mid- 1930s. Since its introduction, MAM has spread
to thirteen states, Connecticut, Delaware, Maryland,
Massachusetts, New Hampshire, New Jersey, New
York, North Carolina, Ohio, Pennsylvania, Rhode Island,
Virginia, West Virginia and the District of Columbia.
cm long and wide. The stems, petioles and leaf veins
are covered with sharp, recurved spines. Leaf nodes
are surrounded by flared, saucer-shaped ochreae.
The pale green flowers, which develop on
stem tips, give way to
clusters of pale green
fruits, becoming iridescent bluish-purple
at maturity. Each fruit
contains a single hard,
black, shiny seed or
achene. Seeds germinate in early March and
April in the northeastern U.S. and are readily
dispersed by water and
animals particularly birds and deer. Traditional control
methods are hand-pulling and repeated herbicide application due to seed bank persistence and viability.
Nature of Ecological Damage
MAM prefers full sun and disturbed sites such as areas
along railroad tracks, power line and highway rightsBiology and Traditional Control
MAM is an herbaceous, annual vine that can grow up of-way, stream banks, forest openings, and recreation
to 6 meters in length in a single growing season. The areas such as parks, where it forms dense thickets, outleaves are alternate, triangular in shape and 2.5 to 7.5 competing most native vegetation. Power line rightsof-way through forested areas create ideal conditions
for seed dispersal and invasion into disturbed areas in
the forest. MAM is also a major concern in reforestation
sites where its fast growth quickly overwhelms and
kills out-planted seedlings, as well as, preventing
regeneration of native species.
Triangular leaves (a), recurved spines (b), and flared ochreae surrounding stems of MAM.
Biological Control
The USDA Forest Service Forest Health Technology
Enterprise Team (FHTET) initiated and sponsored the
biological control project for MAM in 1996, through
cooperation with the University of Delaware and the
Chinese Academy of Agricultural Sciences for natural
enemy surveys and collections in the U.S. and the P.R.
China.
Forest Health Technology Enterprise Team
http://www.fs.fed.us/foresthealth/technology
P R O V I D I N G T E C H N O L O G Y F O R F O R E S T H E A LT H P R O T E C T I O N
MAM infestation out-competes native vegetation.
From 1997 through 2000, over 2,000
specimens, representing 7 orders and 110 families,
were recovered from MAM on 93 sites in four eastern
states in the U.S. However, none of the native
natural enemies were effective in suppressing MAM
populations and no insects that attack the seeds or
roots were recovered.
Between 1996 and 2001 exploration for
natural enemies in 23 northeastern provinces in
P.R. China yielded 111 insect species from six orders
and 29 families. Through subsequent host-range
testing, a weevil, Rhinoncomimus latipes Korotyaev
(Coleoptera: Curculionidae) was selected as the most
promising biological control agent. In 1999 and 2000,
the weevil was imported from China to the Beneficial
Insects Introduction Research quarantine facility in
Newark, Delaware. Host range testing by scientists at
Adult weevil, Rhinoncomimus latipes.
the University of Delaware confirmed R. latipes to be
host specific to MAM only.
The adult R. latipes lays eggs on leaves, stems
and buds. The larvae bore into the stems at the nodes
and feed internally. Once mature, they crawl or drop
to the soil and pupate. Adults emerge from the soil,
crawl up MAM plants, mate and begin laying eggs.
In 2004–2005, surveys and collections of
natural enemies of MAM were conducted in Japan. R.
latipes was the most promising natural enemy of the
50 herbivore insect species collected.
R. latipes was approved for release by USDA
APHIS in 2004. In the spring of 2004 the NJ Department
of Agriculture Philip Alampi Beneficial Insect
Laboratory entered into a cooperative agreement
with FHTET to mass rear the weevil.
In July 2004, the first release of 200 weevils
took place in White Clay Creek State Park, New
Castle, Delaware, with subsequent releases in 2004
in NJ. Since then annual released weevils/states have
increased annually from 12, 509 in three states in
2005 to 76,680 in 11 states in 2012, and 86,060 in ten
states in 2013. A total of 535,562 weevils have been
released in CT, DE, MA, MD, NC, NJ, NY, OH, PA, RI, VA,
and WV including islands in the middle of the Ohio
River.
Post release monitoring techniques and
restoration studies have also been conducted by
scientists at the University of Delaware (Cuttings and
Hough-Goldstein, 2013; Lake et al., 2011; Lake et al.,
2014).
Rhinoncomimus latipes larva feeding in MAM stem.
http://www.fs.fed.us/foresthealth/technology
Forest Health Technology Enterprise Team
P R O V I D I N G T E C H N O L O G Y F O R F O R E S T H E A LT H P R O T E C T I O N
An annual cooperator’s meeting for
biological control of MAM has been held each
year beginning in 2006 to exchange and update
information on MAM distribution, biological
control and related research. A technology transfer
publication “Biology and Biological Control of Milea-Minute Weed” was published in November 2008
(Hough-Goldstein et al., 2008), to document the
progress and results of this biological control effort.
Outlook
R. latipes continues to spread and impact populations
of MAM. Monitored release sites showed reductions
in spring densities of MAM to 25% or less of what they
had been within 1-3 years following weevil release
(Hough-Goldstein et al. 2009). However, the impact of
weevils can vary depending on weather conditions:
cool, wet weather generally favors rampant weed
growth with reduced weevil populations (Lake 2011,
Berg 2014). Impacts also vary depending on the plant
community that co-occurs with the weed. If strong
native competitors are present, biological control
alone can restore a desirable plant community, but if
not, revegetation with native plants may be necessary
along with weevils to suppress MAM and prevent
invasion by other non-native invasive plants (Cutting
and Hough-Goldstein 2013, Lake et al. 2014). Lake et
al. have documented the increase of other invasive
species (e.g. Microstegium vimineum (Japanese stilt
grass)) following reduction of MAM populations on
control sites. Indirect facilitation among invasive
plants was found to be evident between invasive
plant species. Restoration using selected native
plant species incorporated with biological control
and herbicide treatments into an integrated invasive
F OR M O R E INFO RMAT I O N CON TAC T: Richard Reardon, Program Manager
Biological Control and Biopesticide
USDA Forest Service
180 Canfield Street
Morgantown, WV 26505
Phone: 304-285-1566 Fax: 304-285-1564
E-mail: rreardon@fs.fed.us
plant management program may be needed in the
future to manage MAM.
References
Berg, S.H. 2014. Dispersal behavior of the weevil
Rhinoncomimus latipes, and the influence of
varying moisture and temperature conditions
on the biological control of mile-a-minute weed.
M.S. Thesis, University of Delaware, Newark.
Cutting, K., and J. Hough-Goldstein. 2013. Integration
of biological control and native seeding to
restore invaded plant communities. Restoration
Ecology 21:648-655.
Hough-Goldstein, J., E. Lake, R. Reardon, and Y. Wu.
2008. Biology and biological control of mile-aminute weed. Technology Transfer Biological
Control USDA Forest Service FHTET-2008-10.
Hough-Goldstein, J., M. A. Mayer, W. Hudson, G.
Robbins, P. Morrison, and R. Reardon. 2009.
Monitored releases of Rhinoncomimus latipes
(Coleoptera: Curculionidae), a biological
control agent of mile-a-minute weed (Persicaria
perfoliata), 2004-2008. Biological Control 51:450457.
Lake, E. 2011. Biological Control of mile-a-minute
weed, Persicaria perfoliata, and integrating weed
management techniques to restore invaded
sites. Ph.D. Dissertation, University of Delaware,
Newark.
Lake, E., J. Hough-Goldstein, and V. D’Amico. 2014.
Integrating management techniques to restore
sites invaded by mile-a-minute weed, Persicaria
perfoliata. Restoration Ecology 22: (online first).
DOI:10.1111/rec.12035.