Biology and Biological Control of

Mile-a-Minute Weed

Judy Hough-Goldstein, Ellen Lake

Richard Reardon, and Yun Wu

For additional copies of this publication, contact:

Richard Reardon

USDA Forest Service, FHTET

Morgantown

West Virginia

(304) 285-1566

rreardon@fs.fed.us

Judy Hough-Goldstein

Department of Entomology &

Wildlife Ecology

Newark

Delaware

302-831-2529

jhough@udel.edu
Authors

Dr. Judy Hough-Goldstein

Department of Entomology & Wildlife Ecology

University of Delaware

Newark, Delaware

Ellen Lake

Department of Entomology & Wildlife Ecology

University of Delaware

Newark, Delaware

Richard Reardon

USDA Forest Service

Forest Health Technology Enterprise Team

Morgantown, West Virginia

Yun Wu

Plant Pathologist

USDA Forest Service

Forest Health Technology Enterprise Team

Morgantown, West Virginia
i

Acknowledgments

We would like to thank the many land managers, conservation organizations, state parks, and private landowners in Delaware and southeastern Pennsylvania for their assistance 

and cooperation by “donating their mile-a-minute patches to science” while we, beginning in 

2004, implemented and studied the impacts of biological control. Skilled and dedicated insect 

rearers at the Phillip Alampi Beneficial Insect Laboratory in New Jersey were key in developing the program, as were the state and federal cooperators throughout the Northeast who 

assisted with the release and monitoring of the mile-a-minute weevil. And we thank the undergraduates, graduate students, and technicians who assisted with mile-a-minute research at the 

University of Delaware. 

Finally, we would like to thank Chuck Benedict, Information Technology Experts, Inc./USDA 

Forest Service, Forest Health Health Technology Enterprise Team (FHTET), for editing, layout and graphics in this publication, and FHTET for financial support.
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

 iii

Contents

Introduction ......................................................................................1

Overview.....................................................................................................................1

Biological control of weeds..........................................................................................2

About this manual........................................................................................................4

Chapter 1:  Getting to Know Mile-a-Minute Weed ................................5

Description and classification ......................................................................................5

Life history ...................................................................................................................6

Distribution ...............................................................................................................10

Chapter 2: Mile-a-Minute Weed Biological Control Agents ..............11

Basic insect biology ...................................................................................................11

Insects found on mile-a-minute weed in the United States .........................................11

Materials and methods...................................................................................................... 12

Results .............................................................................................................................. 13

Discussion ........................................................................................................................ 16

Insects found on mile-a-minute weed in Asia .............................................................17

China................................................................................................................................ 17

Japan................................................................................................................................. 17

Insects tested in the United States and China for host specificity ................................18

Timandra griseata Peterson (Lepidoptera: Geometridae) .................................................... 18

Rhinoncomimus latipes Korotyaev (Coleoptera: Curculionidae)......................................... 18

Chapter 3. Rhinoncomimus latipes in the United States .......................23

Mass rearing...............................................................................................................23

Release of Rhinoncomimus latipes in New Jersey ......................................................26

Monitored sites ................................................................................................................. 26

Other New Jersey releases................................................................................................. 30

Release of Rhinoncomimus latipes in other states.......................................................32

Release of Rhinoncomimus latipes in replicated release arrays in Pennsylvania ..........33

Dispersal........................................................................................................................... 34

Population growth............................................................................................................. 34

Impact............................................................................................................................... 35

Impact of R. latipes on MAM in field cages...........................................................36
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Biology and Biological Control of Mile-a-Minute Weed ________________________________________

Chapter 4. Biological Control as a Component of an Integrated Milea-Minute Weed Management Program ................................................37

Integrated weed management ....................................................................................37

Weed control methods used to manage MAM................................................................... 37

Education and Prevention.....................................................................................37

Physical or mechanical control methods ..............................................................39

Cultural methods .................................................................................................40

Herbicides ...........................................................................................................41

The biological control component .................................................................................... 43

Planning your program .........................................................................................43

Selecting release sites ...........................................................................................43

Obtaining weevils for biological control...............................................................43

Monitoring weevils...............................................................................................44

Combining biological control with other methods................................................45

Conclusion.................................................................................................................45

Appendices .........................................................................................47

Appendix A: Mile-a-minute weed monitoring protocol, revised, March 2008............47

Introduction ...................................................................................................................... 47

Site selection and quadrat placement................................................................................ 48

Selection ..............................................................................................................48

Quadrat placement...............................................................................................48

Weevil release .................................................................................................................. 50

Spring mile-a-minute survey (Form 1)................................................................................ 50

Summer/fall assessment of weevil abundance, plant damage, and seed production .......... 51

Appendix B: Mile-a-minute weed quick monitoring protocol, July 2008 ...................54

Glossary ...........................................................................................57

References..........................................................................................63

Introduction ...................................................................................................................... 63

Chapter 1: Getting to Know Mile-a-Minute Weed ............................................................ 63

Chapter 2: Mile-a-Minute Weed Biological Control Agents ............................................. 64

Chapter 3: Rhinoncomimus latipes in the United States.................................................... 64

Chapter 4: Biological Control as a Component of an Integrated Mile-a-Minute Weed

 Management Program ............................................................................................... 65
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

v

List of Figures

Figure 1. Mile-a-minute infested landscape. Inset, mile-a-minute terminal, triangular leaf. ................. 1

Figure 2. Counties in United States where mile-a-minute occurs......................................................... 2

Figure 3. Mile-a-minute plant showing triangular leaves, backward-projecting spines, and flared

 ocreae surrounding stems. ................................................................................................... 5

Figure 4. Immature and mature clusters of berry-like fruits on mile-a-minute...................................... 5

Figure 5. Mile-a-minute seedlings in early spring................................................................................ 6

Figure 6. Animal browse on mile-a-minute terminal. .......................................................................... 7

Figure 7. Numbers of mile-a-minute seeds germinating when kept cold (35 – 37° F, Oct. – April)

and when kept warm (65 – 68° F, May – Sept.). .................................................................... 8

Figure 8. Number of seeds that germinated under natural conditions.................................................. 9

Figure 9. Generalized insect morphology.......................................................................................... 11

Figure 10. Complete metamorphosis. ............................................................................................... 11

Figure 11. Adult Rhinoncomimus latipes........................................................................................... 19

Figure 12. Larva feeding in stem. ...................................................................................................... 19

Figure 13. Black and orange weevils................................................................................................. 21

Figure 14. Mile-a-minute (Persicaria perfoliata) cuttings. .................................................................. 23

Figure 15. “Ideal” pruned mile-a-minute plant for weevil rearing. .................................................... 24

Figure 16. Egg-laying container......................................................................................................... 24

Figure 17. Development containers. ................................................................................................. 24

Figure 18. Rhinoncomimus latipes pre-pupa..................................................................................... 25

Figure 19. Field release of Rhinoncomimus latipes............................................................................ 26

Figure 20. Adult weevil feeding damage in early spring.................................................................... 27

Figure 21. Damaged nodes indicating larval feeding......................................................................... 27

Figure 22. Rhinoncomimus latipes egg.............................................................................................. 27

Figure 23. Japanese beetles feeding on mile-a-minute. ..................................................................... 27

Figure 24. Early spring damage to mile-a-minute weed..................................................................... 28

Figure 25. Mile-a-minute, Floodgate Road........................................................................................ 28

Figure 26. Defoliated mile-a-minute, Floodgate Road....................................................................... 28

Figure 27. Weevils............................................................................................................................ 28

Figure 28. Generalized map of release arrays. .................................................................................. 33

Figure 29. Graph of weevil egg production....................................................................................... 34

Figure 30. Graph of weevil population growth at the Laurels............................................................ 34

Figure 31. “Stacked” nodes on weevil-damaged mile-a-minute plants. ............................................. 35

Figure 32. Graph of percent cover of mile-a-minute in early June at the Laurels. .............................. 35
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Biology and Biological Control of Mile-a-Minute Weed ________________________________________

Figure 33. Graph of number of seeds per cluster at three release sites and two control sites.............. 35

Figure 34. Mile-a-minute with heavy weevil damage in field cage.................................................... 36

Figure 35. Graph of survival of individual mile-a-minute plants exposed to weevils in field cages. ... 36

Figure 36. Mile-a-minute distribution in heronry, Pea Patch Island, Delaware. .................................. 38

Figure 37. Mile-a-minute on Pea Patch Island, August 2003.............................................................. 38

Figure 38. Mean number of blue, green, and green immature seeds that germinated after cold

stratification........................................................................................................................ 39

Figure 39. Side terminals produced by mile-a-minute plants that have been mowed......................... 40

Figure 40. Damaged mile-a-minute plant, with competing native vegetation.................................... 40

Figure 41. Frame used for monitoring mile-a-minute and weevils..................................................... 44

Figure 42. Adult weevil, weevil eggs, adult damage, and larval node damage. ................................. 48

Figure 43. Quadrat frame construction diagram................................................................................ 49

Figure 44. Examples of percent defoliation. ...................................................................................... 50

List of Tables

Table 1. Herbivorous insects collected from Persicaria perfoliata in Delaware, Maryland,

 Pennsylvania, and Virginia, 1997–2000. .............................................................................. 14

Table 2. Average number of mile-a-minute seedlings at release and control sites in New Jersey. ....... 29

Table 3. Average percent cover of mile-a-minute at release and control sites in New Jersey. ............. 29

Table 4. Rhinoncomimus latipes releases and recoveries in New Jersey............................................. 30

Table 5. Rhinoncomimus latipes releases and recoveries in states other than New Jersey. ................. 32

Table 6. Commonly used herbicides for mile-a-minute control......................................................... 42

Photo Credits

Figures 1 (inset), 4a, 4b, 6, 11, 20, 21, 24, 31, 39, 40, 42a-d, Ellen Lake, University of Delaware

Figure 2, Yun Wu, USDA Forest Service, Forest Health Technology Enterprise Team

Figures 3, 5, 23, 37, 41, Judy Hough-Goldstein, University of Delaware

Figures 12, Jon K. Gelhaus, Academy of Natural Sciences, Philadelphia, PA, Amy Diercks, New Jersey 

Department of Agriculture

Figures 13a, Kelsey Paras, University of Delaware

Figures 13b, 18, 22, Amy Diercks, New Jersey Department of Agriculture

Figures 14, 15, 16, 17, Dan Palmer, New Jersey Department of Agriculture

Figures 19, 25, Mark A. Mayer, New Jersey Department of Agriculture

Figure 36, Kendall Sommers, Delaware Department of Natural Resources and Environmental Control
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

 1

Introduction

Overview

Mile-a-minute weed (MAM), Persicaria perfoliata (L.) H. Gross (Fig. 1), is a member of the 

family Polygonaceae. It is an annual vine that can grow up to 6 meters long over the course of 

a season. It is widely distributed throughout east Asia, including Japan, China, Korea, India, 

Indonesia, Bangladesh, Siberia, Philippines, Malay Peninsula, Indochina Peninsula, Nepal, and 

Turkey (Wu et al. 2002). It was introduced to the northeastern United States in the mid-1930s 

Figure 1. Landscape infested with mile-a-minute weed.
2 Introduction

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

from Japan, probably as seed unintentionally mixed in with holly seeds, and has since spread to 

ten states and the District of Columbia (Fig. 2). 

Mile-a-minute invades disturbed areas, 

such as roadsides, stream banks, rightsof-way, openings in forested areas, and 

regeneration areas, and crowds out 

most native vegetation. At high densities it can create monocultures. In addition to the loss of native biodiversity, 

with its stems and leaves covered with 

recurved spines, MAM is bothersome 

to people and their pets during outdoor 

activities.

The seed remains viable in the seed bank 

in the soil for six years, so managing 

MAM successfully depends on yearly 

treatments. Herbicides and hand-pulling plants can be effective management 

methods, but these are difficult to accomplish on a landscape with intermittent MAM populations.

The biological control program for MAM began in 1996. That year, the USDA Forest Service, 

Forest Health Technology Enterprise Team (FHTET), together with the University of Delaware and the Chinese Academy of Agricultural Sciences, initiated surveys for natural enemies 

and host-range studies in China and the U.S. In 2001, a colony of the weevil Rhinoncomimus

latipes (initially misidentified as Homorosoma chinensis) was established in the USDA Agricultural Research Service (ARS) quarantine facility in Newark, Delaware, to study its biology and 

life cycle. Host-range studies were initiated with input from the Technical Advisory Group 

(TAG), which represents the interests of a diverse group of Federal and other agencies. A petition for release in the U.S. was submitted to the USDA Animal and Plant Health Inspection 

Service (APHIS) in 2003, and approved in 2004. The New Jersey Department of Agriculture 

began mass rearing the weevil in 2004 and the first release was made in Delaware that same year. 

Subsequent releases have been made in New Jersey, Maryland, Pennsylvania, and West Virginia. 

The search for additional natural enemies of MAM continues in China and Japan.

Biological control of weeds

Problems caused by exotic invasive plants have increased dramatically in recent decades. In 

the US, it is estimated that invasive plant species comprise from eight to 47 percent of the total 

flora of most states (Rejmánek and Randall 1994). Many possess characteristics that favor their 

population increases, and have no natural enemies in their invaded range. So, once they become 

established, they are not easily suppressed or eliminated.

Classical biological control involves reconnecting exotic plants with the specialized natural enemies from their native ranges. This process begins with surveys in the target plant’s area of origin to discover candidate natural enemies, progresses through studies of the candidate’s biology 

and host specificity, and culminates with the release and evaluation of a candidate’s damage to 

Figure 2. Counties in the United States in which mile-a-minute 

occurs.
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

Introduction 3

the target plant. Damages will either limit weed reproduction or facilitate secondary infection 

by pathogens, which in turn will reduce the weed’s ability to compete with other plants. In the 

eastern United States, projects have targeted aquatic, pasture, and forest weeds.

Biological control agents cannot be retrieved once they are released; therefore, they must be 

carefully selected and extensively studied before being approved for release (Wilson et al. 2004). 

The question arises as to what these specialized enemies will eat once they have reduced the 

target-weed population. Specialist insects have evolved over thousands of years to deal with 

specific secondary plant chemicals in their hosts, and cannot easily expand their range to feed on 

other plant species. Where host-range expansions have occurred, they generally have involved 

feeding on plant species that are closely related to the target weed. Therefore, it is critically important to determine, prior to release, whether any closely related desirable plant species occur 

in an area where a release is planned. If so, prior to release, it should be determined whether the 

insect can feed on those species. However, because even the most effective biological control 

agent will only reduce, not eradicate, the target-weed species, the long-term goal of any release 

is for both plant and insect populations to persist, but at relatively low levels.

There are advantages and disadvantages to classical biological control of weeds:

Advantages

•	 It is selective against a specific weed or closely related group of weeds.

•	 It can provide long-term control.

•	 Agents can disperse to areas not accessible to humans or equipment for control.

•	 The biological control agents are self-perpetuating, so there are no recurring 

acquisition, rearing, and reintroduction costs.

Disadvantages

•	 There are high initial program costs.

•	 It is not certainthat the agents will be effective (even effective agents will not 

work in every situation).

•	 There is a risk of unintended, adverse impacts on other plant species (non-target 

effects).

•	 Impacts may not be noticed for five to ten years.

The United States Department of Agriculture, Animal and Plant Health Inspection Service, 

Plant Protection and Quarantine (USDA-APHIS-PPQ) and the Canadian Food Inspection 

Agency (CFIA) are responsible for authorizing the importation of biological control agents into 

their respective countries. Federal laws in the U.S. and regulations are in place to minimize 

the risks to native plant and animal communities associated with introductions of exotic organisms to manage weeds. The Technical Advisory Group for Biological Control Agents of Weeds 

(TAG) is an expert committee with representatives from regulatory agencies, federal land management and environmental protection agencies from the United States, Canada and Mexico. 

TAG is concerned with the safety and potential impacts of prospective biological control agents. 

To that end it reviews all petitions to import new agents into the United States and makes 

recommendations to USDA-APHIS. Weed biological control researchers work closely with 

USDA-APHIS-PPQ and TAG to assess the environmental safety of potential weed biological 

control agents and programs. The Canadian counterpart to TAG is the Biological Control Review Committee (BCRC) (Bourchier et al. 2006).
4 Introduction

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

In addition, each state in the United States has its own approval process to permit field release 

of weed biological control agents.

About this manual

This manual provides background information on mile-a-minute weed and the biological control insect Rhinoncomimus latipes, and provides guidelines for the use of biological control as 

either a stand-alone tactic or as a component in an integrated MAM management program. The 

chapters are:

Chapter 1 provides a detailed description of MAM, including taxonomy, description of the 

leaves, stems, flowers, seeds, and habitat, life history and occurrence in the United States.

Chapter 2 provides the results of surveys for natural enemies of MAM in the US, Japan and 

China. It describes the weevil R. latipes, its biology and host range studies.

Chapter 3 describes the mass-rearing, releases and spread of R. latipes and its impacts on MAM 

in the US.

Chapter 4 includes elements of a biological control program as well as an integrated management program for MAM.

Glossary defines technical terms essential in using and communicating about MAM biological 

control.

References provide critical literature on MAM biology, ecology, and biological control. Only 

publications cited directly in this manual are listed.

Appendices

 A. Mile-a-minute weed monitoring protocol and forms

 B. Mile-a-minute weed quick monitoring protocol and form
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

 5

Chapter 1:  Getting to Know Mile-a-Minute Weed

Description and classification

Mile-a-minute weed is an herbaceous, annual vine with stems that grow up to 6 meters long in 

one growing season. It has triangular leaves, and its stems, petioles and leaf veins are covered 

with small, backward-projecting, recurved prickles. Leaves are alternate, simple, and 2.5 to 7.5 

centimeters long and wide. Ocreae (fused stipules that surround the stem at each leaf node) 

are found in many species in the family Polygonaceae; in MAM they flare widely into a saucer 

shape (Fig. 3). Flower buds, and later 

flowers and fruits, develop at the terminal tips. Flowers are small, green, and 

generally inconspicuous. The flowers 

give way to clusters of green berry-like 

fruits, which turn an iridescent bluepurple when mature (Fig. 4). Each fruit 

encloses a single, hard, shiny, black, 

seed, or achene.

Figure 3. Mile-a-minute weed. Note triangular leaves (a), backwardprojecting spines (b), and flared ocreae surrounding stems (c).Figure 4. Immature (a) and mature (b) berrylike fruit clusters.
6 Chapter 1: Getting to Know Mile-a-Minute Weed

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

Mile-a-minute weed was long classified in the large genus Polygonum, as P. perfoliatum L. 

However, more recently most botanists in North America have agreed that this plant should be 

placed in the genus Persicaria (Hinds and Freeman 2005). Along with other “tearthumbs” (all 

of which have recurved prickles on their stems), this species is in the section Echinocaulon, and 

the scientific name is now Persicaria perfoliata (L.) H. Gross. The North American species that 

are most closely related to P. perfoliata are Persicaria sagittata (L.) H. Gross (arrow-leaf tearthumb), and Persicaria arifolia (L.) Haraldson (halberd-leaf tearthumb). Also, the smartweeds, 

which include both native and introduced species, are now placed in the genus Persicaria.

Life history

In the Northeastern United States, seeds germinate beginning in March or April (Fig. 5). Flowering begins in June or July and fruits may be produced beginning any time from June through 

August, probably depending on both site and weather conditions. Achenes are dispersed 

through human activities and by water, birds, deer and other mammals (see “Dispersal of milea-minute seeds by deer,” below).

Ripe fruits not consumed by animals drop to the soil and many germinate under old plants the 

following spring. The seeds must go through a period of moist cold before they will germinate. 

Seeds can survive for more than one season and retain viability (see “Mile-a-minute seed bank 

persistence and viability,” below). As an annual plant, the entire MAM plant dies with the first 

hard frost, generally in late October or early November in the Mid-Atlantic region.

Figure 5. Mile-a-minute seedlings in early spring.
_________________________________________Biology and Biological Control of Mile-a-Minute Weed

Chapter 1: Getting to Know Mile-a-Minute Weed 7

Dispersal of mile-a-minute seeds by deer

Mile-a-minute (MAM) seed dispersal and germination can be facilitated by white-tailed 

deer, Odocoileus virginianus Zimm. Deer can consume large numbers of a wide variety 

of seeds while they forage (Myers et al. 2004, Vellend 2002). They may travel substantial 

distances before defecating, thus transporting seeds hundreds to thousands of meters, 

and even farther during seasonal migration. In one study, 64% of the plant species that 

germinated from seeds present in deer pellet samples were from non-native species 

(Myers et al. 2004).

As MAM plants mature, seeds ripen and plant stems get woodier near the terminals. 

Plants in the field appear to hold the seed clusters up and out over the mat of vegetation 

(personal observation, E. Lake). Often, these terminal fruit clusters are missing (Fig. 6), 

with only an ocrea and part of the stem left behind. Erica Dale and Ann Herzig (Bryn 

Mawr College, unpublished data) collected deer scat and searched the samples for MAM 

seed. Although large numbers of MAM seed fragments 

were found, many seeds 

also passed through the gut 

intact. In 18 deer pellet 

groups collected in the fall 

of 1997 and 1998, an average of 17.6 intact MAM 

seeds were found per pellet 

group (range 1–111). A germination experiment demonstrated that 40% of MAM 

seed scarified via passage 

through deer gut was viable.

Figure 6. Animal browse on mile-a-minute terminal.
8 Chapter 1: Getting to Know Mile-a-Minute Weed

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

Mile-a-minute seed bank persistence and viability

Judith A. Okay, Riparian Specialist, Virginia Department of Forestry and Chesapeake Bay 

Program, Annapolis Maryland

To assess P. perfoliata seed bank longevity and persistence, two experiments were conducted using achenes collected in the 1997 growing season. The first was a temperaturecontrolled experiment using refrigeration to induce germination, and the second involved 

achenes buried in soil. Each of the tests ran from September 1997 through July 2003.

Temperature-controlled test 

A total of 264 achenes were placed on moist sponges in petri dishes in groups of about ten 

per dish. They were kept in an incubator without lights, and exposed to temperatures that 

simulated seasonal temperature changes, i.e. 35 to 37° F through fall and winter (October 

through April), and 65 to 68° F through spring and summer (May through September). 

Sponges were kept moist, and 

achenes were checked weekly for germination, defined as 

the protrusion of the radicle 

through the seed coat.

The majority of the seeds germinated during the period 

when they were exposed to 

cold temperatures, and most 

germinated during years one 

and two (Fig. 7). However, a 

small number of seeds continued to germinate each year 

through year six. By the end 

of year six, more than 99% of 

the seeds had germinated.

Buried-seed test

In October of 1997, 800 achenes were placed in four mesh bags (200 per bag), marked 

with orange survey flagging and buried side by side in a 3’ x 3’ plot at a depth of 5 to 

6 inches in natural loamy-clay soil. The achenes were not watered or tended, but were 

left in the soil under natural conditions until the following spring. The mesh bags were 

exhumed each spring in late May or early June after a flush of P. perfoliata seedlings had 

emerged in the area of the test plot, indicating most germination had ceased. This was 

done each year from 1998 through 2001, and again in 2003. Undamaged achenes that 

had not germinated were separated from roots and opened husks of germinated achenes, 

counted, returned to the mesh bags, and reburied.

Figure 7. Numbers of mile-a-minute seeds germinating when kept 

cold (35 – 37° F, Oct. – April) and when kept warm (65 – 68° F, 

May – Sept.) from a single batch of 264 mile-a-minute weed achenes 

collected in 1997 (Year 1 = Oct. 1997 – Sept. 1998).

Continued, next page
_________________________________________Biology and Biological Control of Mile-a-Minute Weed

Chapter 1: Getting to Know Mile-a-Minute Weed 9

Mile-a-minute seed bank persistence and viability, continued

Of the 800 achenes buried in 

fall of 1997, over 40% germinated the following spring 

(Year 1, Fig. 8), and an additional 21% germinated the 

second year after burial. Most 

of the remaining seeds germinated at a lower rate over the 

next four years. By 2003 (Year 

6), 99.3% of the buried seeds 

had germinated.

Conclusions

The seasonal dormancy observed in both the temperature-controlled test and the buriedseed test is a common response for summer annuals, which produce seeds that generally 

go dormant in response to the high temperatures of late summer and early fall, and germinate only during the cooler conditions of early spring. The need for a period of cold-wet 

stratification to break seed dormancy in P. perfoliata has been shown by others (summarized by Colpetzer and Hough-Goldstein, 2004), but this is the first test to show this pattern continuing over multiple years with a single batch of seeds exposed sequentially to a 

7-month cold period and a 5-month warm period.

In both experiments, P. perfoliata seed persisted and remained viable in the seed bank for 

6 years following collection, although most of the seed germinated during the first and 

second year. Van Clef and Stiles (2001) reported 32.6% viability of MAM seed that had 

been buried for three years, but did not test longer periods. The results presented here suggest natural resource managers attempting to control P. perfoliata should plan to continue 

control efforts for at least six growing seasons, because viable seed is likely to persist in the 

seed bank for at least that long.

Figure 8. Number of seeds that germinated under natural conditions, buried in mesh bags and exhumed each year (not checked in 

year 5).
10 Chapter 1: Getting to Know Mile-a-Minute Weed

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

Distribution 

Mile-a-minute weed is indigenous to, and widely distributed in, Asia. It was first reported in 

the United States near Portland, Oregon, in the 1890s, but apparently did not persist west of the 

Rocky Mountains. The plant was introduced into the eastern U.S. in the mid-1930s at the Gable Nursery in Stewartstown, Pennsylvania, probably with holly seeds from Japan (Moul 1948). 

Analysis of random amplified polymorphic DNA (RAPD) profiles of MAM populations from 

China, Japan, Korea and the eastern U.S. support the suspected single introduction and Japanese origin of the eastern U.S. population (Shuppert 2001). No genetic variation was detected 

among populations in North America, suggesting an effectively clonal population. Specimens 

from the U.S. sites more closely resembled MAM from Japan than those collected in China and 

Korea, further supporting the likely Japanese provenance of the U.S. population.

Before 1980, MAM was limited to five counties in Pennsylvania and parts of Maryland. By 

1995 it had been reported in 51 counties in seven states plus the District of Columbia (Fig. 2, 

above). An additional 19 counties, some in two new states, Connecticut and New Jersey, were 

added by 2000, and another 41 counties and one new state, Massachusetts, was added between 

2001 and 2008 (Fig. 2, above). Other states in plant hardiness zones 6 and 7 are thought to be 

vulnerable to invasion by MAM in areas where adequate moisture is available (Okay 1997). It 

is not likely that the eastern U.S. population of MAM will progress into more tropical climates 

because those zones lack the cold vernalization period needed to break achene dormancy and 

stimulate germination.

In the U.S., MAM is a weed of parks, preserves, conservation easements, nursery crops, orchards, roadsides, drainage ditches and rights of way. Although it prefers low wet ground and 

full sun, it will tolerate semi-shade. Mile-a-minute appears to be more restricted to moist flood 

plains in Japan and China than in the U.S.
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

 11

Chapter 2: Mile-a-Minute Weed Biological Control Agents

Basic insect biology

Insects are a very large, diverse class of animals. 

Knowing basic insect anatomy and biology 

can help land managers recognize and identify 

biological control insects in the field. Adult 

insects have several unique characteristics: 1) an 

exoskeleton (external skeleton), 2) a segmented 

body comprised of three distinct regions: head, 

thorax, and abdomen, and 3) three pairs of legs 

(Fig. 9). Biological control agents for mile-aminute have a life cycle with four distinct stages 

- egg, larva, pupa, and adult (Fig. 10). This form 

of development is called complete metamorphosis.

Immature insects also have an external skeleton 

that they must shed in order to grow. The process of shedding the exoskeleton is called molting. The stage of the insect between successive 

molts is called an instar. As larvae, insects generally complete three to five molts. The mature 

larva then molts into a pupa, the non-feeding 

stage when the insect changes from a larva to an 

adult.

Insects found on mile-a-minute weed 

in the United States

One of the earliest surveys for natural enemies 

associated with mile-a-minute weed was conducted by Wheeler and Mengel (1984) in south 

central Pennsylvania in 1981 through 1983. 

They recovered more than 30 insect species (five orders, 15 families) that developed on MAM 

and 12 species that appeared to use the plant only for adult feeding. All 30 of these species 

Figure 10. Complete metamorphosis.

Figure 9. Generalized adult insect anatomy.
Biology and Biological Control of Mile-a-Minute Weed ________________________________________

12 Chapter 2: Mile-a-Minute Weed Biological Control Agents

caused only minor herbivory. There were no leafminers, stem borers, internal fruit feeders, or 

gall makers. Three relatively oligophagous species were identified: Lithacodia [now Pseudeustrotia] carneola Guenee (Lepidoptera: Noctuidae), Calothysanis amaturaria Walker (Lepidoptera: Geometridae), and Ametastegia sp. (Hymenoptera: Tenthridinidae). All three species 

were rare.

Two surveys for native natural enemies of MAM were initiated in the late 1990s in the eastern 

U.S. in an effort to identify native natural enemies of MAM and their relative effectiveness (prior to the release of exotic species of natural enemies). The first was an effort by Jim Fredericks, 

M.S. student at the University of Delaware. Fredericks surveyed MAM populations in White 

Clay Creek State Park in New Castle County, Delaware; Elk Neck State Park in Cecil County, 

Maryland; Eastern Neck Island in Kent County, Maryland; and Pennypack Park in Philadelphia 

County, Pennsylvania in 1997 (Fredericks 2001). He collected insects associated with MAM 

once a week from June through October. He collected a total of 35 insect species, 21 of which 

were not previously reported to be associated with the plant. No internal stem or seed feeders 

were identified, supporting the observations of Wheeler and Mengel. Fredericks did not recover 

the three oligophagous species recovered by Wheeler and Mengel. Fredericks attempted to rear 

C. amaturaria on MAM, but the larvae failed to feed and died.

The second effort was a broader survey of various habitats that documented the accumulation 

of natural enemy species and their associated damage on MAM and evaluated their potential as 

biological control agents. This effort was conducted in Pennsylvania, Maryland, Delaware, and 

Virginia, from 1997 through 2000. The results of this broader survey are reported here.

Materials and methods

In 1997, 37 sites of various sizes and habitats containing MAM were located by the State 

Departments of Agriculture or Forestry in Delaware (2 sites), Maryland (16 sites), Pennsylvania (8 sites) and Virginia (11 sites). The center of each site was marked with a 6-foot metal 

stake, a photo was taken to represent the density of MAM, and GPS coordinates were recorded. Additional data for each site, including abundance of MAM, habitat type, and other 

plant species growing in association with P. perfoliata, were recorded. Each site was visited 

once every two weeks from June through September and insects were either hand-picked 

or aspirated from MAM plants, or collected by shaking plants over a white sheet. Most of 

the insects were collected on the leaves; other parts of the plants were also examined in an 

attempt to recover root borers, stem borers, and internal fruit feeders. Type and severity of 

damage and the plant parts affected were also recorded. Attempts were made to keep immature Lepidoptera alive and rear them to maturity; adult Lepidoptera were placed in a kill jar, 

and all other insect specimens were placed in 70% ethyl alcohol (ethanol). Field collectors 

provided initial taxonomic identification to family prior to submitting the completed forms 

and insect specimens to research associates in the Entomology Department at West Virginia 

University, who, in turn and when possible, provided the initial identification to genus and 

species. Identifications to genus and species were then confirmed by taxonomic specialists, 

including Drs. Linda Butler (Lepidoptera), John Strazanac (Orthoptera), Dave Smith (Symphyta), Shawn Clark (Coleoptera), and Charles Bartlett (Hemiptera, suborder Auchenorrhyncha). Portions of the sample areas were monitored again in 1998 (24 sites), 1999 (19 

sites) and 2000 (13 sites).
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Chapter 2: Mile-a-Minute Weed Biological Control Agents 13

Results

During the four-year study, over 2,000 specimens were recovered from P. perfoliata, representing seven orders and 110 families. However, many of these were known to be nonherbivores. Abundantly recovered phytophagous species were the oriental beetle, Anomala 

orientalis Waterhouse (Coleoptera: Scarabaeidae); Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae); and meadow grasshoppers, Conocephalus spp. (Orthoptera: Tettigoniidae). Table 1 shows insects recovered from P. perfoliata that were likely 

to be phytophagous on MAM, including polyphagous insects that are known to feed on P. 

perfoliata, polyphagous insects that are known to feed on Persicaria or Polygonum species, 

and very polyphagous insects that might feed on species in these genera or related plants. 

Seventeen species of insects were common to this survey and the one conducted by Wheeler 

and Mengel (1984). Larvae of the fall webworm, Hyphantria cunea (Drury), were recovered 

in both surveys in the United States and this was the only species also recovered from MAM 

in China and in Japan (Miura 2008).

Numerous insect species were observed on, or collected from, MAM, although most were 

not actually observed either feeding on or causing damage to P. perfoliata. Those few insect 

species that were observed damaging MAM plants were polyphagous species that either 

might or are known to feed on Polygonaceae or related plants. Of these species, the most 

abundantly recovered phytophagous species was the Japanese beetle, P. japonica, followed 

by, in decreasing order of abundance:

•	 tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) [Hemiptera, suborder 

Heteroptera: Miridae]

•	 potato aphid, Macrosiphum euphorbiae (Thomas) [Hemiptera, suborder 

Sternorrhyncha: Aphididae] 

•	 locust leafminer, Odontota dorsalis (Thunberg) [Coleoptera: Hispinae] 

•	 a small stink bug, Mormidea lugens (F.) [Hemiptera, suborder Heteroptera: 

Pentatomidae]

During August, P. japonica adults were especially abundant on all of the sites in each of the 

four states. In some areas, the adults defoliated 80 to 100% of the MAM plants in a localized area as well as individual plants. The defoliated plants recovered and continued to 

grow and produce quantities of viable seed.

The habitat of each site was recorded as being either partly sunny dry, partly sunny wet, full 

sun dry, or full sun wet. In its native range, P. perfoliata seems to persistently occupy wet 

sites (e.g., edges of creeks and rivers) whereas in this survey it occupied both wet sites and 

drier upland sites (e.g., roadsides, forest edges) (Table 1). In the upland sites, organic matter (leaves, plant material, etc) may be required to enhance seed germination and/or to keep 

the shallow root system moist and cool (Mountain, 1989). Many of the other plant species 

associated with MAM are also considered invasive weeds, including multiflora rose (Rosa 

multiflora), crownvetch (Coronilla varia), Canada thistle (Cirsium arvense), and garlic mustard (Allaria petiolata).
Biology and Biological Control of Mile-a-Minute Weed ________________________________________

14 Chapter 2: Mile-a-Minute Weed Biological Control Agents

Order (suborder) 

Familya Species Relativefrequencyb

Part sun Full sun Other 

surveys Wet Dry Wet c Dry

Polyphagous species known to feed on mile-a-minute weed

Coleoptera

 Chrysomelidae Odontota dorsalis (Thunberg) R X X W

 Scarabaeidae Anomala orientalis Waterhouse C X

Popillia japonica Newman C X X X X W

Hemiptera (Heteroptera)

 Miridae Halticus bractatus (Say) R X X

Lygus lineolaris (Palisot de Beauvois) O X X X X W

 Pentatomidae Acrosternum hilare (Say) R X X X X W

Euschistus servus (Say) R X X X

Euschistus tristigmus (Say) R X X X W

Hemiptera (Auchenorrhyncha)

 Acanaloniidae Acanalonia bivittata (Say) R X X X W

 Cicadellidae Graphocephala coccinea (Forster) R X X X X W

Graphocephala versuta (Say) O X X X W

 Flatidae Metcalfa pruinosa (Say) R X X X X W

Hemiptera (Sternorrhyncha)

 Aphididae Macrosiphum euphorbiae (Thomas) R X X X X W

Lepidoptera

 Arctiidae Estigmene acrea (Drury) R X W

Spilosoma virginica (F.) R X X W

 Geometridae Calothysanis amaturaria (Walker) R X W

 Noctuidae Palthis asopialis (Guenée) O X X X

Orthoptera

 Acrididae Melanoplus differentialis (Thomas) R X X X W

 Tettigoniidae Amblycorypha oblongifolia (DeGeer) R X X X W

Amblycorypha rotundifolia (Scudder) R

Atlanticus sp. R X X X

Conocephalus brevipennis (Scudder) R

Conocephalus sp. C X X X X

Scudderia furcata Brunner R X X X W

Table 1. Herbivorous insects collected from P. perfoliata in DE, MD, PA, and VA, 1997 – 2000.

a

Orders, suborders (Hemiptera only), and families as in Triplehorn and Johnson (2005).

b

Relative frequency: R, rare, taken at one or two sites in one state, usually in small numbers; O, occasionally collected at two or more sites in one or two states; C, common, taken at most sites in more than two states.

c

Other surveys: D : also listed as associated with mile-a-minute in China (Ding et al. 2004); W: also listed as associated with MAM in Pennsylvania (Wheeler and Mengel 1984).
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

Chapter 2: Mile-a-Minute Weed Biological Control Agents 15

Table 1, continued. Herbivorous insects collected from P. perfoliata in DE, MD, PA, and VA, 1997 – 2000.

 Order (suborder) 

Familya Species Relative

frequencyb

Part sun Full sun Other 

surveys Wet Dry Wet c Dry

Polyphagous species known to feed on Polygonaceae

Coleoptera

 Chrysomelidae

Diabrotica undecimpunctata 

Mannerheim R X X W

Diachus auratus (F.) R X X X

Disonycha glabrata (F.) R X

Luperaltica senilis (Say) R X X X X

Hemiptera (Heteroptera)

 Miridae Halticus sp. R X X X

 Thyreocoridae Corimelaena sp. R X X

Lepidoptera

 Arctiidae Pyrrharctia isabella (Smith) R X

 Geometridae Prochoerodes tranversata (Drury) R X

 Tortricidae Sparganothis sulfureana (Clemens) R X

Orthoptera

 Acrididae Melanoplus sanguinipes (F.) R X X X

 Tettigoniidae Microcentrum sp. R X

Very polyphagous species that might feed on Polygonaceae

Coleoptera

 Chrysomelidae Epitrix fuscula Crotch R X

Oulema sayi (Crotch) R X X X

 Curculionidae Myllocerus hilleri Faust R X X X

Otiorhynchus ovatus (L.) R X X X X

Hemiptera (Heteroptera)

 Berytidae Jalysus sp. R X X X

Neides muticus (Say) R X X X

 Coreidae Leptoglossus sp. R X X X

 Cydnidae Sehirus cinctus (Palisot de Beauvois ) R X X

 Miridae Adelphocoris sp. R X X X

Stenodema trispinosa Reuter R X X X

Stenodema vicinum (Provancher) R X X X

 Pentatomidae Holcostethus limbolarius (Stal) R X

Menecles sp. R X X X

Mormidea lugens (F.) R X X X X

Nezara sp. R X X X X

 Rhopalidae Arhyssus sp. R X

a

Orders, suborders (Hemiptera only), and families as in Triplehorn and Johnson (2005).

b

Relative frequency: R, rare, taken at one or two sites in one state, usually in small numbers; O, occasionally collected at two or more sites in one or two states; C, common, taken at most sites in more than two states.

c

Other surveys: D : also listed as associated with mile-a-minute in China (Ding et al. 2004); W: also listed as associated with MAM in Pennsylvania (Wheeler and Mengel 1984).
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16 Chapter 2: Mile-a-Minute Weed Biological Control Agents

Discussion

In this survey there was no evidence of seed or root feeders even though adults of several 

families of Coleoptera (e.g., Elateridae, Scarabaeidae) were recovered, and their immatures 

are associated with polyphagous root feeding. Many taxa were recovered from MAM foliage but few were associated with herbivory. Aphids were recovered on leaves and stems of 

many plants but the damage was minimal (less than 1%) on individual plants. Obviously, 

there has been an accumulation of taxa on MAM but at least 90% are transient or highly 

polyphagous.

P. perfoliata appeared to be equally abundant in moist and dry sites in this survey, although 

the quantity of organic matter might be a critical factor on the drier sites. In its native range, 

MAM is associated with moist sites; therefore, populations are probably regulated by seasonal flooding as well as natural enemies.

Under optimal conditions plants can compensate for the negative effects of herbivory; 

therefore, both the timing and duration of defoliation are important factors in regulating the 

host. Popillia japonica was the most abundant defoliator of MAM but had minimal impact 

on the survival and seed production of individual plants.

 Order (suborder) 

Familya Species Relativefrequencyb

Part sun Full sun Other 

surveys Wet Dry Wet c Dry

Very polyphagous species that might feed on Polygonaceae, continued

Hemiptera (Auchenorrhyncha)

 Cercopidae Philaenus spumarius (L.) R X X X X

 Cicadellidae Draeculacephala mollipes (Say) O X X X X

Oncometopia orbona (F.) O X

Paraulacizes irrorata (F.) R X X X

Tylozygus bifidus (Say) R X X X

 Membracidae Entylia carinata (Forster) C X

Hemiptera (Sternorrhyncha)

 Aphididae Aulacorthum solani (Kaltenbach) R X

Lepidoptera

 Arctidae Hyphantria cunea (Drury) R X D.W

a

Orders, suborders (Hemiptera only), and families as in Triplehorn and Johnson (2005).

b

Relative frequency: R, rare, taken at one or two sites in one state, usually in small numbers; O, occasionally collected at two or more sites in one or two states; C, common, taken at most sites in more than two states.

c

Other surveys: D : also listed as associated with mile-a-minute in China (Ding et al. 2004); W: also listed as associated with MAM in Pennsylvania (Wheeler and Mengel 1984).

Table 1, continued. Herbivorous insects collected from P. perfoliata in DE, MD, PA, and VA, 1997 – 2000.
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Chapter 2: Mile-a-Minute Weed Biological Control Agents 17

Insects found on mile-a-minute weed in Asia

China

In 1996, a collaborative project was initiated between USDA Forest Service, Forest Health 

Technology Enterprise Team (FHTET) and the Chinese Academy of Agricultural Sciences 

Institute of Biological Control (now Institute of Environment and Sustainable Development 

in Agriculture) to survey and screen biological control agents of MAM in China for possible 

release in the eastern U.S. Surveys for phytophagous insects were conducted from 1996 to 

2001 in 23 provinces including some in northeastern China, where the climate is similar to 

that of the eastern United States, and southwest China, which is considered the center of 

origin of the family Polygonaceae (Ding et al. 2004).

A total of 111 phytophagous species from six orders and 29 families were associated with 

MAM in China. Although most were leaf feeders, several stem borers, fruit feeders, and 

seed feeders were found. No insects were recovered from the roots. Eleven of the species 

were regarded as important because either they cause severe damage on MAM or have a narrow host range (Ding et al. 2004). Included among the species collected were:

•	 the weevil Rhinoncomimus latipes Korotyaev (Curculionidae)

•	 three oligophagous leaf beetles, Smaragdina nigrifrons (Hope) (Eumolpidae), 

Gallerucida bifasciata Motschulsky and Galerucella placida Baly (both 

Chrysomelidae)

•	 a moth, Timandra griseata Peterson (Geometridae)

•	 a hemipteran, Cletus schmidti Kiritschenko (Coreidae)

•	 the sawfly, Allantus nigrocaeruleus (Smith) (Tenthredinidae)

Japan

In 2004 and 2005, Dr. Kenji Fujisaki at Kyoto University initiated a survey for herbivorous 

insect fauna of MAM. Parts of Japan are in the native range of MAM (Ohwi 1965) and 

many of the survey sites are a good climatic match to the northeastern United States (Miura 

et al. 2008). Fujisaki conducted surveys at 15 sites from Kagoshima in the south to Sapporo 

in the north. They consisted of timed visual surveys (15 min per sample, two to six samples 

per site on a given sample date) with only one or two visits per year to most of the sites. A 

total of 50 herbivorous insect species were recovered on MAM:

•	 26 Hemiptera (52%)

•	 11 Lepidoptera (22%)

•	 9 Coleoptera (18%)

•	 3 Orthoptera (6%)

•	 1 Hymenoptera (2%)

Six species appeared to be potential Polygonaceae specialists:

•	 2 Hemipterans, the bug Coptosoma parvipictum Montandon (Pataspidae) and 

aphid Trichosiphonaphis ishimikawae (Shinji) (Aphididae)
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18 Chapter 2: Mile-a-Minute Weed Biological Control Agents

•	 2 Lepidopterans, Timandra apicirosea (Prout) (Geometridae) and Oligonyx 

vulnerata (Butler) (Noctuidae)

•	 1 Sawfly, Allantus luctifer Smith (Tenthredinidae)

•	 1 Beetle, Rhinoncomimus latipes Korotyaev (Curculionidae) (Miura et al. 2008)

Of the six specialist herbivores, R. latipes appeared to be the most promising natural enemy. 

This observation supports results from surveys conducted in China, as well as host-range 

testing, and the release of R. latipes, in the U.S. (Miura et al. 2008).

In 2006 and 2007, additional surveys for natural enemies of MAM were conducted by Dr. 

Naoto Kamata at the University of Tokyo. Twelve habitats with sites established along rivers or streams in the suburbs of the Tokyo Metropolitan area were monitored. Mile-a-minute weed appeared above ground in mid-May, began to decline in early October, and disappeared by mid-November. These sites were scouted for insects once or twice a week from 

the middle of May to the end of November. During each scouting session, at least 400 stems 

of MAM were inspected for 2 to 3 hours. In total, eight species of herbivorous insects were 

recovered on MAM in 2006: Allantus luctifer (sawfly), Hyphantria cunea (moth), Timandra 

apicirosea (moth), Cifuna locuples confusa (moth), Orgyia thyellina (moth), Helicoverpa armigera (moth), Apoderus erythrogaster (Attelabidae), and Rhinoncomimus latipes (weevil). 

Another moth, Spodoptera litura, was recovered in 2007. The weevil R. latipes was the most 

common herbivorous insect. It fed only on MAM in choice and no-choice tests. As was 

reported in the Fujisaki surveys in 2004 and 2005, the moth Timandra apicisocea was recovered in fairly abundant numbers in 2006 and 2007. It was dismissed as a potential biological 

control agent for release in the U.S. because, based on the results of no-choice tests, it also 

fed on common buckwheat (Fagopyrum esculentum Moench), tartary buckwheat (F. tartaricum Gaertn.) and rhubarb (Rheum rhabarbarum).

Insects tested in the United States and China for host specificity

Timandra griseata Peterson (Lepidoptera: Geometridae)

In August 1999, Ding Jianqing, with the Institute of Environment and Sustainable Development in Agriculture (formerly the Chinese Academy of Agricultural Sciences Institute 

of Biological Control) in Beijing, collected larvae and pupae of Timandra griseata from the 

field in Henan and Hubei provinces and sent them to the USDA-ARS Beneficial Insects 

Introduction Research (BIIR) quarantine facility in Newark, Delaware. T. griseata defoliated potted MAM, developing from egg to adult in approximately 26 days. However, its 

host range was considered to be too broad for it to be released in the United States, because 

it also fed and developed on common buckwheat (Fagopyrum esculentum Moench) and 

tartary buckwheat (F. tartaricum Gaertn), and accepted these species and MAM equally in 

choice tests (Price et al. 2003).

Rhinoncomimus latipes Korotyaev (Coleoptera: Curculionidae)

Adults of R. latipes (initially misidentified as Homorosoma chinensis Wagner) were collected 

in Changsha, Henan province in China by Ding Jianqing and sent to the BIIR quarantine 

laboratory in July of 1999 and 2000 (Fig. 11). These weevils were found to have a relatively 
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Chapter 2: Mile-a-Minute Weed Biological Control Agents 19

high reproductive rate and short generation time on potted MAM. Adults lay eggs on 

MAM leaves or stems. Eggs hatch in about 3 days (Price et al. 2003). Larvae quickly bore 

into stems at nodes, and feed internally (Fig. 12). Once fully grown, they crawl or drop to 

the soil where they pupate. The new adults emerge from the soil, crawl up nearby MAM 

plants, mate, and begin laying eggs.

In tests in China, R. latipes did not feed 

on 28 species of plants in 18 families 

outside of the Polygonaceae. Within the 

Polygonaceae, adult R. latipes did not 

feed on any plant other than MAM in 

choice tests or lay eggs on any species 

other than MAM, and larvae survived 

only on MAM. In quarantine in Newark, 

Delaware, R. latipes did not oviposit or 

complete larval development on two crop 

plants, buckwheat and rhubarb, within 

the family Polygonaceae, (Price et al. 

2003). Subsequent tests were conducted 

on representatives from all of the Sections 

within the genus Polygonum sensu lato 

and on representatives of genera other 

than Polygonum within the family Polygonaceae, especially genera that contain threatened 

and endangered species. Also included were representatives of families thought to have 

chemical affinities with the Polygonaceae. Adult weevils in these tests fed and survived on 

a few species, but did not lay any eggs on plants other than MAM. In choice tests adults 

almost exclusively ate MAM, and newly hatched larvae placed on other plant species did 

not survive (Colpetzer et al. 2004). Based on these results, a release permit was granted by 

USDA-APHIS in July of 2004.

In the field in China, adults of R. latipes were collected from the upper petiole and the upper surface of the lamina, particularly on the first or second youngest leaves of MAM plants 

(Ding Jianqing, personal communication). Adults fed externally by scraping the epidermal 

layer and underlying cells, usually penetrating through to the other side of the leaf to form 

Figure 11. Adult Rhinoncomimus latipes.

Figure 12. Larva feeding in stem.
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20 Chapter 2: Mile-a-Minute Weed Biological Control Agents

a characteristic feeding hole. Newly hatched larvae bored into the young stem or bud from 

the top, and then tunneled downwards inside the stem. The combination of heavy defoliation by adult weevils and larval stem boring caused leaves to desiccate and curl until young 

shoots gradually withered away.

There are at least two generations of weevils per year in China. They overwinter as adults 

and emerge in early to mid-May when MAM vines are 12 to 15 inches long (Ding Jianqing, 

personal communication). High adult weevil populations have been observed in July, when 

they can be collected easily from MAM, often as mating pairs. Typically, three or four weevils per plant are found at this time, but in an exceptional year there could be as many as six 

to ten weevils per plant.

Host specificity testing

Matthew J. Frye, PhD student, University of Delaware

Host specificity testing of potential weed biological control agents is an essential step in 

determining the safety and efficacy of the insect or pathogen under evaluation. The primary objective of these tests is to determine the physiological host range of the agent, i.e. 

in addition to the target weed, which plant species from the introduced range are suitable 

for insect feeding, development, and reproduction.

The first step in host specificity testing is to develop a list of plants that may be at risk 

of damage from an imported phytophagous insect. This list must be reviewed by the 

Technical Advisory Group (TAG), an independent committee that reports to the USDA 

Animal and Plant Health Inspection Service. Test-plant species are selected based on 

their phylogenetic (evolutionary) relationship to the target weed, focusing primarily on 

species closely related to the target. The list of test plants also may include host plant species compiled from historical accounts of a potential agent, host plants of insects closely 

related to a potential agent, plant species that share morphological and biochemical 

traits or habitat requirements with the target weed, and crop and ornamental plants of 

economic value.

After a potential biological control agent has been selected from field surveys and preliminary tests in the native range of the target weed, the insect should be sent to a quarantine 

facility in the country where it is to be introduced for further evaluation. Included in the 

evaluation are no-choice tests in which insects are presented with a single, non-target, 

test-plant species at a time. Feeding, development, and survival rates are recorded and 

compared to those for insects on the target weed. No-choice oviposition tests are conducted to assess whether a female will oviposit (lay eggs) when confined to a single test 

plant. Tests used to determine the insect’s host specificity may include choice tests, in 

which insects are presented with a combination of test-plant species along with the target 

weed, and their oviposition or feeding is recorded. Choice tests may include all plant 

species used by adults for oviposition as well as plant species from the no-choice tests fed 

upon by insects in any life stage. 
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Chapter 2: Mile-a-Minute Weed Biological Control Agents 21

In culture in China, females began to oviposit 2 to 8 days after copulation, and continued to 

oviposit for 80 to 100 days. Tests with 25 pairs of adults showed that mean egg production 

was about 180 per female (Ding, unpublished data). No parasites were found in weevils collected as adults or in laboratory cultures. No insect pathogens were observed in the field or 

laboratory.

In quarantine in Newark, Delaware, the total development time (egg to adult) averaged 26 

days, and egg production averaged about 130 eggs per female (Price et al. 2003). Adults 

from the previous year were observed to live through August and into late September in the 

laboratory, indicating that they can live up to 1 year. Adult R. latipes are black upon emergence, but turn orange-brown soon after feeding on MAM (Fig. 13).

Figure 13. Black (a) and orange (b) weevils.

_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

 23

Chapter 3. Rhinoncomimus latipes in the United States

Mass rearing

Dan Palmer, Amy Diercks, and Caryl Ott

In August, 2004, mass rearing of R. latipes was initiated at the New Jersey Department of Agriculture’s Phillip Alampi Beneficial Insect Laboratory (PABIL), in West Trenton, New Jersey. 

The lab was specifically designed for mass rearing insects. Rearing is on-going, with continual 

improvement in methods and efficiency.

It is well known that the quality of host material is paramount to successful insect rearing. 

Seeds collected from the field were initially used to propagate the plant. The seed-scarification 

process required for germination proved to be very time consuming, so vegetative reproduction 

was tried. It proved to be successful, and the use of cuttings from “mother plants” replaced the 

seed method of propagation. Standard growing procedures in the greenhouse were investigated 

to determine the needs of the plant. Good conditions include:

•	 fertilizer (ScottsTM General Purpose/Peter’s Professional® ammonium nitrate fertilizer, 20-20-20), strength of 200 ppm

•	 day and night greenhouse temperatures of 75° F and 65° F respectively

•	 care in frequency of watering

•	 Fafard® mix for soil medium

•	 6-inch plastic pots

•	 a 7-week-old plant

A healthy mother plant provides thick 

stems to use for cuttings. Replacing these 

plants approximately every 5 weeks ensures 

the supply of good cutting material and 

avoids greenhouse pests. The two lower 

nodes of the cutting (trimmed 0.25-inch 

below the lowest node and with the leaf 

cut off of both lower nodes) are soaked in 

rooting hormone for 10 seconds and then 

placed in plastic containers with individual 

compartments filled with a moist mixture 

of vermiculite and milled sphagnum moss 

(Fig. 14). The cuttings are placed in a shal- Figure 14. Mile-a-minute weed (Persicaria perfoliata)

cuttings.
Chapter 3: Rhinoncomimus latipes in the United States

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

24

low bin under fluorescent lights at 82° F and 100% humidity for 2 weeks. After a 3-day graduated venting process, the cuttings are transplanted into pots, watered, misted, and covered loosely with plastic for 1 day. The plants are 

placed in the greenhouse four days after 

transplant. Watering is carefully monitored to avoid over-watering.

A precision pruning technique was developed to keep the plants at a manageable size while still providing the terminals (growing tips) needed for weevil 

reproduction. Female R. latipes lay 

most of their eggs on plant terminals; 

newly hatched larvae only burrow into 

the very young leaf nodes on a terminal. 

A plant with a sturdy base and five to 

eight thick-stemmed terminals is bestsuited for insect production (Fig. 15).

Plants are kept under grow lights 

through all insect rearing stages to optimize plant quality leading to increased 

weevil production. Room temperatures are kept at 80° F with 16L: 8D lighting conditions. The 

Tek-5 grow lights are used to maintain the temperature inside the containers at about 82° F. The 

humidity inside both the egg laying and the development containers is between 95 and 100%. 

For egg laying, mating pairs of R. latipes are placed on seven-week-old MAM plants inside the 

containers (Fig. 16). Eggs start hatching on day three or four. Every 2 to 3 days, the plants are 

moved to development containers (large plastic bins) and new plants are added to the egg-laying 

containers (Fig. 17).

Figure 15. “Ideal” pruned mile-a-minute plant for

weevil rearing.

Figure 16. Egg-laying container. Figure 17. Development containers.
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

Chapter 3: Rhinoncomimus latipes in the United States 25

As the eggs hatch, the larvae burrow into the youngest leaf nodes and develop through all larval instars within the nodes and stems. Because many of the leaf nodes occupied by the larvae 

are new growth that began at about the time the eggs were laid, grow lights are needed over the 

development bins. Seven or 8 days after egg hatch, the mature larvae chew their way out of 

the nodes and either crawl or drop to 

the moist soil medium below, where 

they pupate (Fig. 18). At this point the 

foliage inside the bin is replaced with 

a “trap plant.” The pre-pupa builds a 

capsule around itself with the soil medium attached to the outside and pupates 

inside the capsule. After spending the 

pre-pupal and pupal stages in the soil, 

the adults emerge between day 17 and 

20 and crawl up the trap plant to feed, 

where they can be collected using an 

aspirator. 

The adults are either stored in a cage 

with an abundance of MAM plants or, 

if to be shipped soon, placed in a release cup with a honey-water sponge 

and kept at 55° F until shipped. Three 

methods are being evaluated for storing 

adults during the winter:

•	 Some adults are put in cages with large MAM plants and left outdoors through fall 

and winter to have the weevil go through a natural winter season.

•	 Some are put in a cage indoors with abundance of MAM plants, kept at 55° F, and 

brought out to feed at 74° F three times a week.

•	 Others are stored in moist sphagnum moss in Ziploc® bags at 34° F after pre-conditioning on MAM plant material, first for one week at 65° F, then for another week at 

55° F, until feeding is reduced.

An organization could use similar procedures to rear R. latipes in its own facilities. The insects 

should be reared in a room kept at 80° F (or 82° F inside the container). The egg-laying containers can be clear plastic display boxes with a “no-see-um” netting covering a 1.5-inch hole in 

the top. The development containers can be polycarbonate clear plastic bins with three, 2-inch 

holes on each side covered with netting, and lids with three 2-inch holes covered with netting. 

The bins will keep the environment humid, so humidity inside the room may not be a concern. 

Grow lights over both oviposition and development containers are very important. The maximum rearing temperature inside the containers is around 88° F. If temperatures inside the containers drop below 78° F, the insects will have a longer life cycle.

Figure 18. Rhinoncomimus latipes pre-pupa.
Chapter 3: Rhinoncomimus latipes in the United States

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

26

Release of Rhinoncomimus latipes in New Jersey

Mark Mayer

Monitored sites

In addition to mass rearing R. latipes, PABIL personnel have released the weevils at numerous sites in New Jersey, several of which have been monitored using the “Mile-a-Minute 

Monitoring Protocol” developed by Dr. Judy Hough-Goldstein (Appendix A). Four field 

sites were set up for monitoring, three in Southern New Jersey (two at Floodgate Road in 

Greenwich, Gloucester County, and one at Department of Defense [DOD] Ponds Wildlife 

Management Area [WMA] in Pilesgrove, Salem County), and one in Central New Jersey 

at Pinelands Water and Wastewater Company in Vincentown, Burlington County. Weevils 

were released on two sites, and two were monitored as control sites. The control sites did 

not receive weevils, but MAM populations were monitored for comparison with release 

sites.

In spring, 2005, PABIL field personnel established two new sites in Salem County and 

dropped the Vincentown and the DOD Ponds sites, because these sites had been disturbed 

frequently by the public and there was a possibility that chemical control measures had 

been implemented. The new 2005 release site was at the Abbotts Meadow Wildlife Management Area in Elsinboro Township; the control site was located in the Supawna Meadows 

National Wildlife Refuge in Pennsville Township. One of the two Floodgate Road sites was 

retained as a release site and the other as a control site.

For all releases, weevils were brought to the field in 16-oz. wax-lined, hot-beverage Sweetheart® cups with holes cut into each end (Fig. 19). Nylon mesh was secured over the holes 

and a Pioneer plastics® Petri dish containing 

a sponge moistened with honey and water 

was taped to the bottom of the cup. Excelsior 

was placed in the cup to give the weevils more 

resting sites. Upon release, the excelsior and 

any weevils on it were removed from the cup 

and placed gently on the MAM. The cup was 

placed in the MAM to allow the rest of the 

weevils to walk out on their own.

Figure 19. Field release of Rhinoncomimus latipes.
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

Chapter 3: Rhinoncomimus latipes in the United States 27

Weevil counts can be misleading, because they tend to drop, undetected, from the plant 

when disturbed during the survey process. Often, weevils can be found by first looking 

for feeding damage near the release site (Fig. 20), and then by searching for them on nearby 

leaves and terminals. Another sign of weevil activity in the field is the presence of damaged 

nodes (Fig. 21), indicating areas where larvae have bored into or out of stems. Although 

they are very tiny, the presence of weevil eggs (Fig. 22), with their characteristic peanut 

shape and thin covering of frass strips (insect fecal material), is another definitive sign of 

weevil activity. Foliage damage alone is not always adequate proof of weevil presence, because other organisms can also feed on MAM, notably Japanese beetles, which can be found 

on the plants in July and August (Fig. 23). Although not definitive proof of infestation, 

where weevils occur, feeding holes on MAM often make the plant stand out among other 

Figure 20. Adult weevil feeding damage in early 

spring.

Figure 21. Damaged nodes, indicating larval feeding.

Figure 22. Rhinoncomimus latipes egg. Figure 23. Japanese beetles feeding on mile-a-minute.
Chapter 3: Rhinoncomimus latipes in the United States

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

28

plant species (including other closely related plant species), especially in early spring 

(Fig. 24).

The Floodgate Road release site in Gloucester County received 200 weevils in July 

2004 and 3,297 in 2005. The weevils established quickly; the population grew so 

rapidly, the MAM was completely defoliated by October 2006 (Figs. 25, 26). There 

were so many weevils present at that site 

that more than 200 were collected in under 

a minute simply by putting a clipboard under the defoliated stems and gently tapping 

the plants (Fig. 27). The large numbers of 

weevils present in October 2006 indicated 

there was potential to establish field insectaries. To that end, in September of 2007, 

200 weevils were collected from defoliated 

plants and redistributed on a site in Hunterdon County.

Figure 24. Early spring damage to mile-a-minute 

weed (note that the closely related Persicaria sagittata is untouched).

Figure 25. Mile-a-minute at Floodgate Road July 2004 (left), in October 2006 (middle) and October 2007 (right) 

after R. latipes feeding. Note the Prunus sp. bush in the foreground (middle) was not visible prior to weevil release 

in 2004 (left), because it was covered by mile-a-minute. The Prunus sp. grew once mile-a-minute was reduced.

Figure 26. Defoliation at Floodgate Road, October 2006. Figure 27. Weevils on clipboard, October 2006.
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

Chapter 3: Rhinoncomimus latipes in the United States 29

Between 2005 and 2006, MAM seedlings were counted each spring in each of the ten permanent quadrats (see Monitoring Protocol, Appendix A) at the release and control sites (Table 

2). Although the spring seedling count increased at Floodgate Road between 2006 and 2007, 

the MAM plants were significantly suppressed by the weevils in 2007. Over the course of 

the season, many MAM plants could not compete against other plant species, and seedling 

numbers were much lower in spring of 2008 (Table 2). The control site at Floodgate Road 

was so overrun with weevils migrating from the release site, it could no longer serve as a 

control site after 2006.

Following release of nearly 7,000 weevils between April and September, 2005, both the 

spring seedling counts and percent of MAM cover at Abbott’s Meadow were dramatically 

reduced (Tables 2 and 3). In contrast, both seedling counts and percent cover remained high 

at the control site.

In 2006, a large number of R. latipes adults emerged after overwintering at Abbott’s Meadow. Heavy feeding by these adults depleted the available MAM and apparently triggered 

weevil dispersal. In 2006 R. latipes was recovered 4 kilometers (2.5 miles) from the original 

release site and by the end of the 2007 season, R. latipes was recovered from, and had caused 

feeding damage to, MAM 5.6 kilometers (3.5 miles) from the release site.

Site

Number of

R. latipes

released in 2005

Spring

2005

Spring

2006

Spring

2007

Spring

2008

Floodgate Road 

 Release 3,297 290.4 ± 39.3 132.0 ± 25.5 207.6 ± 63.6 31.5 ± 10.4

 Control 349.3 ± 52.0 161.6 ± 22.5 -- --

Abbott’s Meadow

 Release 6,976 401.0 ± 20.6 30.0 ± 12.4 93.5 ± 29.5 8.1 ± 5.9

 Control 484.0 ± 73.6 505.2 ± 128.3 457.4 ± 87.7 192.8 ± 71.8

Table 2. Average number of mile-a-minute seedlings (± SEM) at release and control sites in New 

Jersey.

Site

Number of

R. latipes

released in 2005

Spring

2005

Spring

2006

Spring

2007

Spring

2008

Floodgate Road 

 Release 3,297 55.5 ± 5.9 47.0 ± 10.6 35.4 ± 10.3 12.1 ± 3.6

 Control 60.0 ± 6.5 55.0 ± 7.7 -- --

Abbott’s Meadow

 Release 6,976 45.0 ± 3.1 4.2 ± 2.0 9.4 ± 4.9 1.8 ± 1.0

 Control 60.5 ± 6.8 66.9 ± 7.7 77.5 ± 8.1 37.6 ± 8.7

Table 3. Average percent cover of mile-a-minute (± SEM) at release and control sites in New 

Jersey.
Chapter 3: Rhinoncomimus latipes in the United States

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

30

Other New Jersey releases

Between 2004 and 2007, PABIL released a total of 64,911 R. latipes adults into eight New 

Jersey counties (Table 4). Adult R. latipes and/or their feeding damage were observed in 

2007 at eight of nine (88.9%) 2006 release sites. Overall, since 2004 the weevils have been 

recovered from 35 out of 37 (94.6%) of the sites (Table 4). That no weevils were recovered 

at two sites in Hunterdon County could have been due to rocky and dry conditions, and the 

fact that the weevils that were released were a mixture of new weevils and old weevils used 

for rearing. Also, because the releases took place in October the weevils may not have had 

sufficient time to acclimate before winter’s onset.

Two of the release sites in New Jersey have been subjected to flooding. One of the 2005 

Washington Crossing sites (Table 4) was located along the Delaware River and experienced 

a “100 year flood” in spring, 2006. The high waterline was two feet above the release site 

and no weevils were expected to survive; nevertheless, R. latipes adults were recovered at the 

release site in late May. Weevils were recovered from another site, along the Delaware River 

on the DOD Ponds Wildlife Management Areas in Salem County, even though it was periodically flooded by tides.

Adult R. latipes have dispersed from release sites in New Jersey, and some have migrated 

across the Delaware River to Amico Island. This ability to disperse is important because, 

despite weevil releases and other control activities, MAM is being found more frequently 

and over a greater range each year in New Jersey.

Table 4. Rhinoncomimus latipes releases and recoveries in New Jersey.

County Location Dates Number

Released

2008 

Recovery

2004 Releases

Gloucester Floodgate Road (shipped from the University of Delaware) 7/28 200 Y

2005 Releases

Salem Abbott’s Meadow WMA 4/22–9/9 6,976 Y

Mercer Washington Crossing State Park, near open air theater 5/13–5/18 652 Y

Mercer Washington Crossing State Park, near Delaware River 5/18 270 Y

Gloucester Floodgate Road 6/17–8/29 3,297 Y

Salem DOD Ponds WMA 10/12 600 Y

2005 Total 11,795

2006 Releases

Burlington Pinelands Water Co. 4/28 2,260 Y 

Burlington Taylor’s Farm 5/5 1,066 Y 

Gloucester Floodgate Road by Lake 5/12 800 Y 

Mercer Washington Crossing State Park 5/19 1,050 Y

Salem Supawna Meadows NWR for U.S. Fish & Wildlife Service 6/9–9/29 15,692 Y 

Salem Mesogianes Farm 9/1 1,125 Y

Hunterton Hunterdon County Park 10/13 600 N

Hunterdon Round Valley Rd 10/13 397 Y

Hunterdon Pine Bank Rd 10/13 600 Y

2006 Total 22,465
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

Chapter 3: Rhinoncomimus latipes in the United States 31

Table 4, continued. Rhinoncomimus latipes releases and recoveries in New Jersey.

County Location Dates Number

Released

2008 

Recovery

2007 Releases

Salem Lighthouse Road. 5/4 1,202 Y

Salem Supawna Road 3 locations 5/4, 5/11 3,364 Y

Gloucester Davidson Road 5/11 2,100 Y

Hunterdon Dreabrook Road 5/18 1,800 Y

Salem Killcohook spoils off Finns Point access road 5/25 4,513 Y

Hunterdon Railroad Avenue 5/18 600 Y

Salem Harris Road 5 locations 6/1 1,800 Y

Salem Mesogianes Farm 6/1 827 Y

Middlesex Rutgers Horticultural Farm 6/15 719 Y

Salem Gant Farm 6/29 1,802 Y

Salem Pennsville-Auburn Road 7/13 1,161 Y

Salem Pinyard Road 7/20 2,049 Y

Warren Delaware Lake 7/27 1,200 Y

Salem Fort Mott Road 8/3 1,200 Y

Salem DOD Ponds WMA parking lot 8/9 671 Y

Union Watchung Reservation 8/16 1,894 Y

Salem Hook Road 8/24 1,998 Y

Bergen Overpeck Preserve 8/30 741 Y

Salem Park Avenue 9/5 351 Y

Hunterdon Pine Bank Road (field collected from Floodgate site) 9/13 200 Y

Hunterdon Pine Bank Road (lab weevils) 9/14 300 Y

Hunterdon Route 29 (one year old weevils) 10/5 159 N

 2007 Total 30,651

 Total 64,911
Chapter 3: Rhinoncomimus latipes in the United States

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32

Release of Rhinoncomimus latipes in other states

Weevils were released in Delaware in 2004 at two sites within White Clay Creek State Park 

(Table 5). Site 1 was a diverse site with a variety of other plant species, especially Rubus sp., and 

various trees and shrubs. Mile-minute weed was greatly suppressed within the first year at this 

site, and by 2008 very little MAM could be found except at the sunny, exposed edges. Site 2 was 

more of an open monoculture, and MAM persisted through 2008; however, by that same year 

weevils and damaged plants were abundant, Rubus was out-competing MAM in sunny areas, 

and Japanese stiltgrass (Microstegium) was out-competing it in the shade.

State County Location Dates Number 

Released

2008 

Recovery

Delaware 2004 Releases

New Castle White Clay Creek State Park (2 sites) 7/21–28 400 Y

2006 Releases

New Castle Peterson Marsh 6/9 1,200 Y

2007 Releases

New Castle Pea Patch Island 6/13 1,070 Y 

New Castle Peterson Marsh 7/3 900 Y

Maryland 2006 Releases

Cecil Garrett Island 6/16 500 Y

2007 Releases

Cecil Garrett Island 6/18 600 Y

Howard Meadowbrook Park 7/12 500 Y

Pennsylvania 2005 Releases

Chester Laurels, BVA-CREP, BVA-Wetland

(3 sites) 6/9 1350 Y

York Codorus State Park (2 sites), PSECU 

Bldg. 6/1–7/13 610 Y

2006 Releases

Franklin Letterkenny Army Depot 5/4–6/2 1800 Y

Dauphin Wildwood Lake Sanctuary 6/2 600 Y

Potter Sinnemahoning State Park 7/27 600 Y

2007 Releases

Montgomery Pennypack Ecological Restoration Trust 5/23–7/9 3500 Y

Dauphin Wildwood Lake Sanctuary (2 sites) 6/14 300 Y

West Virginia 2005 Releases

Wood Muskingum Isl., Ohio Rivers NWR 

(2 sites) 6/10 400 Y

2006 Releases

Wood Neal Island, Ohio Rivers NWR 6/16 1000 Y

Table 5. Rhinoncomimus latipes releases and recoveries in states other than New Jersey.
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

Chapter 3: Rhinoncomimus latipes in the United States 33

Weevils have been released on Muskingum Island in the Ohio River Islands National Wildlife 

Refuge in West Virginia. They have dispersed throughout the island’s 100 acres, across the Ohio 

River onto the mainland on both sides, and over 5 miles upriver. Weevils were released on Neal 

Island in 2006 and have spread throughout its 105 acres. A third release was conducted on Wells 

Island in 2008. Additional releases have been conducted in Delaware, Maryland, and Pennsylvania (Table 5, above); however, it is too soon to assess the results of these releases.

Release of Rhinoncomimus latipes in replicated release arrays in 

Pennsylvania

Weevil dispersal, population growth, and impact in the field were studied in three replicated 

release arrays in Chester County, Pennsylvania (Lake 2007). One array was located at the 

Brandywine Conservancy’s Laurels Preserve and the other two at the Brandywine Valley Association (BVA) Myrick Conservation Center (BVA-CREP and BVA-Wetland sites). Each array consisted of a central release point surrounded by a total of 76 monitoring points: 60 points 

placed on concentric circles spaced 5 meters apart to a maximum distance of 25 meters (Fig. 28); 

eight points 1 meter from the release; and eight points approximately 2.5 meters from the release. On June 9, 2005, 450 weevils were released in the center of each array.

Figure 28. Generalized release and monitoring array for replicated releases.

Generalized Map of Release Arrays
Chapter 3: Rhinoncomimus latipes in the United States

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34

Dispersal

During the first three months following release, weevils had dispersed 15 to 25 meters 

within the arrays. Four months after release, long-distance dispersers were found up to 200 

meters (0.12 miles) away. Within 14 months, weevils were found in MAM patches nearly 

800 meters (0.5 miles) from the release. Dispersing weevils had located both large MAM 

populations and small isolated patches (Lake 2007). In 2007, approximately 27 months post 

release, weevils were found at several sites within 5.6 kilometers (3.5 miles) of the release 

points and at one site approximately 8 kilometers (5 miles) away. By June 2008, three years 

post release, weevils were observed on numerous MAM weed patches 11.3 kilometers (7 

miles) from the original release sites. These patches ranged in size from small isolated vines 

to large infestations. As of July, 2008, the farthest-removed weevil dispersal was observed 

29 kilometers (18 miles) from the nearest release sites.

Population growth

Weevils were active in the field from early spring through fall and completed at least three or 

four generations. In 2005, 2006, and 2007, the proportion of monitored MAM weed quadrats that contained eggs decreased from 

60% in late August to zero in early October (Fig. 29). This decrease occurred before 

a substantial temperature drop, but coincident with a decrease in day length.

The percent cover of MAM varied greatly 

among monitoring points in the release 

arrays. In order to evaluate the weevil 

population in the context of different MAM 

cover, the number of weevils per monitoring quadrat was divided by the percent 

cover of MAM in that quadrat to generate 

the number of weevils per m2

 of MAM. 

For each site and year, the area under the 

curve for quadrats within 5 meters of the 

release was calculated based on the number 

of weevils per m2 of MAM. At the Laurels 

it was found that weevil density increased 

significantly from 2005 to 2006 and from 

2006 to 2007 (Fig. 30).

The average intrinsic rate of increase of the 

weevil population was estimated at 2.08 in 

2005 and 5.03 in 2006. These rates are comparable to or exceed those of other successful biological control agents.

Figure 30. Weevil population growth at the Laurels.

Figure 29. Weevil egg production (proportion of 

sampled quadrats with eggs, average of all three sites 

each year).
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

Chapter 3: Rhinoncomimus latipes in the United States 35

Impact

In addition to experiencing 

significant loss of photosynthate, damaged plants typically had stem nodes that 

were very close together 

(“stacked” nodes) (Fig. 

31). The percent cover of 

MAM declined significantly 

between 2005 and 2007 at 

the Laurels (Fig. 32). The 

decline in percent cover at 

the BVA CREP site was 

close to significant and 

cover was unchanged at the 

BVA Wetland. The number 

of MAM seedlings per 0.5 

m2 declined significantly 

between 2006 and 2008 at two of the 

three release arrays. At the Laurels—

the array with the largest monoculture 

of MAM, as well as the largest weevil 

population—the number of seedlings 

declined from more than 100 seedlings 

per 0.5 m2

 in 2006 to fewer than 20 in 

2008.

Weevil feeding significantly reduced the 

number of MAM seed clusters between 

2005 and 2007 at two of the three release arrays. This damage also resulted 

in fewer seeds per cluster at the weevil 

release sites than at control sites with 

limited weevil activity. Two control 

(undamaged) sites averaged 12 seeds per 

cluster, while the Laurels had approximately 6 seeds per cluster (Fig. 33). The 

BVA sites had much smaller weevil 

populations than the Laurels had, but 

still had a significant reduction in the 

number of seeds per cluster compared 

to the controls.

Figure 31. “Stacked” nodes on weevil-damaged mile-a-minute 

plants.

Figure 32. Mile-a-minute weed percent of cover in early June at 

the Laurels.

Figure 33. Number of seeds per cluster at three release sites and two 

control sites.
Chapter 3: Rhinoncomimus latipes in the United States

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

36

Impact of R. latipes on MAM in field cages

The impact of R. latipes feeding on P. perfoliata was studied in field cages over a 2-year 

period (Hough-Goldstein et al. 2008; Fig. 34). In 2006, 20 weevils introduced into cages with single plants in May (when weevils first emerge from overwintering) suppressed 

seed production for about 9 weeks, whereas 

weevils introduced in June (when the first 

summer generation of adults emerge) did 

not affect seed phenology. Plants in all 

cages produced substantial numbers of 

seeds late in the year, but the average seed 

(achene) weight was reduced for plants with 

20 weevils per plant introduced in May.

In 2007, plants grown within field cages, 

but with some competition from other 

plants, showed substantial mortality. By 

mid-August, 63% of plants with 10 or 20 

weevils, and 75% of plants with 40 weevils 

per plant were dead, compared with 12.5% 

mortality for control plants (Hough-Goldstein et al. 2008) (Fig. 35). Reproduction 

was delayed by more than a month in surviving plants with 10 or 20 weevils, and by 

more than 2 months in the few survivors with 40 weevils. Surviving plants with 40 weevils per plant showed loss of apical dominance, which can allow plants to compensate 

for herbivore damage; however, in the case of a light-adapted vine such as P. perfoliata, 

this may prevent the plants from achieving needed sun exposure. These results suggest 

that R. latipes feeding on P. perfoliata can impact plant growth and reproduction, and 

may put affected plants at a substantial competitive disadvantage.

Figure 35. Survival of individual mile-a-minute plants exposed 

to 0 (Control), 10, 20, or 40 weevils in field cages in 2007.

Figure 34. Mile-a-minute with heavy weevil damage in 

field cage.
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

 37

Chapter 4. Biological Control as a Component of an

Integrated Mile-a-Minute Weed Management Program

Integrated weed management

Integrated weed management (IWM), an offshoot of the concept of integrated pest management 

that was applied first to insect pests and subsequently to plant disease pests, is rapidly gaining 

acceptance among weed scientists (Buhler 2002). Among the key elements of integrated pest 

management are the use of multiple control tactics and the integration of a thorough knowledge 

of pest biology into the management system. Elements of IWM systems may include: 

Education and prevention

•	 Physical or mechanical control

•	 Cultural methods

•	 Herbicides

•	 Biological control

The ultimate goal of an effective weed management program in a natural area is to replace undesirable plants that cause resource, economic, habitat, or aesthetic losses with a plant or plants 

that are beneficial to the environment. The short-term objective is to implement the most effective combination of control methods available for the target weed. Concurrently, landowners and managers should develop a long-term plan for managing undesirable plants and maintaining desirable vegetation.

Weed control methods used to manage MAM

Education and Prevention

Because mile-a-minute weed is still expanding its range (Fig. 2, page 2), and is patchily 

distributed even in areas where it is well entrenched, efforts to increase public awareness 

of this noxious weed are important to the success of any area-wide integrated management program. Mile-a-minute weed can grow to unmanageable proportions within a 

fairly short time of establishing itself in a new area. For example, the plant was first 

noticed in very small patches in 2001 in the heronry on Pea Patch Island, Delaware. The 

extent of infestation was mapped in 2002, when the population was still small, and in 

2003 and 2004, when populations exploded (Fig. 36). Although not mapped, populations on the remainder of the island outside of the heronry increased in a similar pat-
38 Chapter 4: Biological Control as a Component of an Integrated Mile-a-Minute Weed Management Program 

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

tern (Fig. 37). Populations of MAM 

remained extremely high from 2005 

through 2008. Weevils were released in 

2007 and 2008, and their progress is being monitored. 

MAM can respond rapidly to disturbance. For example, in 2003 MAM was 

probably present on a Chester County, 

Pennsylvania, site slated for development, but the weed was not a problem 

at that time. In the spring of 2004, soil 

disturbance occurred during testing 

to determine septic feasibility. By the 

spring of 2008, the site was a virtual 

monoculture of MAM, with an average of 86 seedlings per square meter (E. 

Lake, unpublished data).

In areas where MAM is present, land 

managers must anticipate the potential 

for it to colonize and/or dominate disturbed sites. It can also dominate land cleared for 

restoration projects. For example, a preserve in Chester County, Pennsylvania, decided 

to convert a site with a mixture of woody and herbaceous invasives, including MAM, to 

a native meadow. Heavy equipment and herbicides were used to prepare the site in the 

fall of 2007, and a mixture of native grasses and wildflowers was seeded. The following 

spring, the site was a monoculture of MAM with little to none of the desirable vegetation visible. 

Eradication may be possible where a population is still small. For example, a nursery 

in Kingston, Rhode Island, has successfully controlled a small infestation through hand 

Figure 36. Mile-a-minute distribution in heronry, Pea Patch Island, 

Delaware.

Figure 37. Mile-a-minute on Pea Patch Island, Delaware, August 

2003.
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

Chapter 4: Biological Control as a Component of an Integrated Mile-a-Minute Weed Management Program 39

pulling and mowing, though an occasional plant still recurs and is removed (R. Casagrande, Univ. Rhode Island, personal communication).

Physical or mechanical control methods 

Mile-a-minute weed has a relatively weak root system, and small plants can be handpulled easily. Gloves should be worn to protect the skin from the plant’s sharp spines. 

Longer vines can be pulled out using a garden rake, as has been done in parts of Little 

Paint Branch Park, near Beltsville, Maryland (Marc Imlay, personal communication). 

Regardless of the method used, to avoid spreading seed to new locations weeds should 

be pulled before they set seed.

Even green seed can germinate (see “Germination of mature and immature seed”); 

therefore, if any seed clusters are present, plants should be removed from the area and 

the seed destroyed. Adequate methods of destroying MAM seed have not been confirmed through research, but experiments on other types of weed seeds suggest possible 

Germination of mature and immature seed

A common reaction of land managers to the appearance of seed clusters on an uncontrolled MAM infestation is to attempt to remove the vines or apply post-emergent 

herbicides (personal observation). It was not known whether viable green seed was present 

at the time these management techniques were implemented, and if this management strategy 

could further the spread of MAM and increase the seed bank.

Blue, green (full sized but green) and green immature (green and not full sized) fruits 

were collected from MAM vines in the fall of 2004. The fruits were dried and the perianth was removed leaving only the achenes. Achenes were separated into groups of 

twenty, put into Ziploc® plastic bags with moist peat moss and placed in a refrigerator 

for cold stratification on June 29, 2005. After approximately 7 weeks, seeds were removed from the refrigerator and the bags were placed in a greenhouse (Colpetzer and 

Hough-Goldstein 2004). One week later the seeds were removed from the peat moss 

and checked for germination. The 

seeds were categorized as: no sign 

of germination, seed split, radicle 

present or cotyledon present.

A proportion of green MAM seed 

was shown to be viable (Fig. 38); 

therefore, removal and/or movement 

of vines with green seed could contribute to the spread of MAM and 

add viable seed to the seed bank. 

Managers should take the potential 

viability of green seed and the annual variation in the timing of seed 

development into consideration 

when implementing management 

techniques.

Figure 38. Mean number of blue, green, and green 

immature seeds that germinated after cold stratification 

(20 seeds per sample).
40 Chapter 4: Biological Control as a Component of an Integrated Mile-a-Minute Weed Management Program 

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

methods. For example, high temperatures in an active compost pile can destroy weed 

seed, but internal temperatures need to reach at least 60° C (140° F) for 7 days to kill 

weed seeds (Rynk 1992). It is very difficult to reach these temperatures near the surface 

of compost piles, so only weed seeds in the interior of the pile are killed (Gordon et al. 

2001). Therefore, to ensure all seeds are exposed to the internal temperatures, compost 

piles need to be turned or mixed periodically. Burning can kill seeds, but the fire must 

be very hot. Work in Australia suggests that 400 °C (750°F) for 20 to 30 seconds may 

be required for hard-coated seeds (Walsh and Newman 2006), so simply putting vines in 

a trash barrel and burning them may not be adequate. Ultimately, until more effective 

seed-killing methods are determined, land managers should make every effort to control 

the plant before seed clusters develop.

Where practical, mile-a-minute weed can be mowed. However, while low mowing may 

kill plants, leaving too much of the plant above ground can release apical dominance 

(Fig. 39) and cause re-growth of sturdy bushy plants, possibly with more terminals and 

a consequent increase in the potential to produce more seed clusters.

As noted earlier, MAM seed can persist and remain 

viable for 6 years in the seed bank. Even if plants 

are removed or killed by physical means, the efforts 

must continue for several years to exhaust any remaining seed bank.

Cultural methods 

Observations and experiments suggest that MAM 

does not thrive in the shade; therefore, one important component for controlling it long-term is to 

add shade trees wherever practical and desirable. 

Competition with other plants is also key in determining whether MAM can dominate a site. Fostering desirable plants, whether by planting or relying 

on natural populations, should be part of a management plan (Fig. 40).

Figure 39. Side terminals produced by mile-aminute plants that have been mowed.

Figure 40. Damaged mile-a-minute plant, with competing 

native vegetation.
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

Chapter 4: Biological Control as a Component of an Integrated Mile-a-Minute Weed Management Program 41

Herbicides

Kevin Fryberger, Preserve Manager, Brandywine Conservancy, Chadds Ford, PA, and 

Art Gover, Research Support Associate, Dept. of Horticulture, Penn State University, 

College Park, PA.

Mile-a-minute weed is quite susceptible to a number of herbicides, including both 

pre- and post-emergent products. Pre-emergent herbicides control plants before they 

emerge from the ground by injuring the plant as the seed germinates. They can be applied to soil and will enter the plant through the roots or shoots emerging from the germinating seed. Post-emergent herbicides act on plants after they have emerged from 

the ground, entering the plant through the foliage or stems. Some herbicides work both 

ways.

Effective control using herbicides is easiest early in the season, before seed set and before MAM begins to climb onto neighboring plants. Depending on weather, seasonal 

conditions, and the herbicide you choose, pre-emergent herbicides should be applied 

between early March and early April. An advantage of pre-emergent applications is that 

most of the existing perennial species will not be affected, particularly if you apply prior 

to bud break.

Post-emergent herbicides may be selective or non-selective. Glyphosate is a widely used 

non-selective herbicide. When used on very dense stands or monocultures of MAM, 

it will provide effective control with minimal damage to non-target plants. However, 

when MAM is growing among desirable plants, it may be very difficult or tedious to 

avoid contacting the non-target plants. If most of the desirable plants are grasses or 

grass-like, a selective herbicide such as triclopyr (‘Garlon® 3A’) can be useful. Triclopyr 

will control MAM without injuring grasses, but will injure on contact other broadleaf 

forbs, shrubs, and trees. Other effective post-emergent products include Journey®, Plateau®, Overdrive®, Escort®, and Milestone® VM.

Adding a surfactant is recommended for better control of MAM with post-emergent 

sprays. Surfacants improve herbicide effectiveness by increasing the spray’s adherence 

to the leaf surface, reducing the surface tension of the mixture so that it spreads over 

more of the leaf, and aiding penetration of the waxy outer cuticle of the leaf, all of which 

promotes better uptake of herbicide into the treated leaf.

Several herbicide products are readily available for both consumer and commercial applicators. Generally, consumer products are less concentrated, and come in smaller 

containers than commercial products. Any of the commercial products listed in Table 

6, below, could be purchased for home use: none of them are “Restricted Use” meaning 

the purchaser need not be a state-certified pesticide applicator. However, if you buy a 

commercial product for residential use you will likely end up purchasing much more 

material than you will need. Although the unit cost of commercial products is lower, 

the larger container size can make them too expensive for small-scale use. Plus, you 

must store or dispose of the surplus product, safely.

Commonly used pre-emergent (PRE) and post-emergent (POST) herbicides are listed 

in Table 6, below. Pre-emergent herbicides commonly used to control MAM are not 

readily available as consumer products. The herbicide pendimethalin is available in 

some crabgrass-prevention products, but often includes fertilizer and is intended for use 

on established turfgrass.
42 Chapter 4: Biological Control as a Component of an Integrated Mile-a-Minute Weed Management Program 

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

There are many factors to consider when selecting an herbicide, including time of year, 

surrounding vegetation, rate of infestation, herbicide volatility and translocation. Factors that can cause variation in results include rainfall during or immediately after application, and drought. Drought-stressed plants are usually less responsive to herbicide 

applications than are actively growing plants.

The ability of a restoration site to recover from weed competition once the weeds have 

been removed will determine short- and long-term management decisions. Complete 

control may not be feasible. The most efficient and effective strategy results from a 

thorough understanding of the environmental forces in the area and a management goal 

that works with and not against these forces. There are many techniques for controlling 

MAM. Usually, the control on a site will require a combination of two or more methods. What will be common to every site is that, owing to the prolific nature of MAM 

and the persistence of the seed bank, periodic monitoring over many years will be required to prevent a disruption to the aesthetic and ecology of a site.

Herbicide Pre or post

emergent

Homeowner product name

and concentration

Commercial product name

 and concentration

pendimethalin Pre Halts® Crabgrass Preventer (1.7 %)

Pendulum® AquacapTM 39% 

Pendulum® 3.3 EC 37% 

Pendulum® 2G 2%

imazapic Both None Plateau® (Govt. only) 24% 

Journey® (plus glyphosate) 8%

sulfometuron Both None Oust® XP 60%

glyphosate Post

Many 1% 

Many 18% 

Many 41%

Roundup® Pro 41% 

Rodeo® 54%

triclopyr Post Roundup® Poison Ivy & Tough 

Brush Killer 8%

Garlon® 3A 44% 

Garlon® 4 62%

a Brand names are listed for reference only. All herbicides listed are available in other products as well. Glyphosate

is so widely available that homeowner product examples are listed by common concentrations rather than brand 

names.

Table 6. Commonly used herbicides for mile-a-minute control.
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

Chapter 4: Biological Control as a Component of an Integrated Mile-a-Minute Weed Management Program 43

The biological control component

Planning your program

Rhinoncomimus latipes has only been available for release against MAM in the U.S. for 

a few years; therefore, we have limited information concerning the weevils’ success and 

population growth under various conditions. We need much more experience and research to determine optimum release rates and methods.

In areas where the MAM population is a massive monoculture that must be controlled 

quickly, such as where trees have been planted and are in danger of being overrun, it is 

probably wise to plan multiple modes of attack. Such a plan would include the application of pre-emergent herbicide in areas where other valued annual plants are not likely 

to be harmed; fostering or planting desirable plant species as competitors; and releasing 

weevils, which over time should increase their populations to the point where they will 

permanently suppress the target plant and help promote a healthy, diverse ecosystem.

Selecting release sites

Rhinoncomimus latipes are present and abundant on MAM throughout China, from 

north to south, so there is no obvious reason why weevil populations should not establish and develop throughout the current and future MAM range in North America. So 

far this has been the case. Weevils have established populations at nearly all sites where 

they have been released. In the mid-Atlantic region they can develop three to four overlapping generations over a single season (Lake 2007). Because of the cooler temperatures in more northerly regions, we would expect fewer generations, and therefore it 

may take more time for large populations to develop further north.

After release and while the insect populations are developing, at least a portion of the 

selected release site should remain undisturbed by other methods of control, e.g., herbicides, mechanical methods, etc. The site selected should be one where the MAM population can be tolerated for several years.

Obtaining weevils for biological control

R. latipes will be commercially available from the Phillip Alampi Beneficial Insect 

Laboratory (PABIL), New Jersey Department of Agriculature, in April, 2009. In states 

where weevils have been established, weevils can be moved legally from one site to another within the state. As weevil populations increase, cooperative extension agents 

may hold “field days” at sites where large numbers of weevils are produced, encouraging homeowners and landowners with MAM infestations to come and collect weevils 

for release at their own sites.

Weevils can be reared if resources are available (see Chapter 3, Mass Rearing); however, 

they can be shipped or transported across state lines only if a USDA-APHIS-PPQ 526 

permit is obtained in advance. The form for requesting this permit, along with other 

relevant information, is available online, at http://www.aphis.usda.gov/plant_health/

permits/organism/index.shtml.
44 Chapter 4: Biological Control as a Component of an Integrated Mile-a-Minute Weed Management Program 

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

Monitoring weevils

In order to document effects of biological control on the target plant population, it is 

important to keep accurate records of when, where, and how many biocontrol insects 

are released, and track the population of the insects and their subsequent impact on both 

the target weed and the entire plant community. Ideally, to make sure that any observed 

changes are not due simply to varying or seasonal conditions, or that they would have 

occurred with or without the introduced insect, one would keep track of several weed 

populations that are exposed to the insect and other, similar weed populations not exposed to the insect. That said, if an introduced insect is a successful biological control 

agent, sooner or later its population is likely to increase to the point that any control site 

will be invaded by the insect, at which time the site will cease to function as a control.

The MAM monitoring protocol has gone through several iterations as we have gained 

experience with the plant and the weevil. The initial protocol was based on monitoring 

protocols for purple loosestrife and garlic mustard developed by Bernd Blossey, Victoria Nuzzo, and coworkers (http://www.invasiveplants.net/). The 2008 version of 

the MAM monitoring protocol is included here as Appendix A, and the latest version is 

available online at http://ag.udel.edu/enwc/research/biocontrol/mileaminute.htm.

The MAM monitoring protocol is designed to track the population of the weevil and 

the MAM population over time. Ten permanent 0.5- by 1.0-meter quadrats, numbered 

1 – 10, are established in a heavily infested MAM patch where weevils are to be released, 

and ten quadrats are established in a similar control site approximately 500 meters away. 

Weevils are then released in quadrat #5 of the first array. The full monitoring protocol 

calls for a spring sample, where MAM seedlings and weevils are counted within a quadrat frame (Fig. 41). Once a month following the spring sample, weevils observed within 

quadrats are counted, the percentage of leaf area removed by insects is estimated, and 

presence or absence of node damage indicating weevil reproduction is noted. Later in 

the season the number of mature and immature fruiting terminals is counted. The percentage of MAM cover in each quadrat is estimated during each survey. The expectation 

is that as the weevil population increases, 

the percentage of MAM cover will be reduced in the quadrats.

Recognizing that not all land managers 

who release weevils have the labor or 

time resources to follow the complete 

monitoring protocol, we have developed 

an alternative “quick” protocol (Appendix B). This protocol involves physically 

marking the site where weevils have been 

released, and going back three times per 

year (spring, summer, and fall) to observe 

whether weevils, weevil feeding damage, 

and node damage can be observed within 

a 1-meter radius of the release site. In 

addition, the approximate percentage of 

MAM and other plant coverage is estiFigure 41. Frame used for monitoring mile-a-minute and weevils. mated at each site. The sites should be 
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

Chapter 4: Biological Control as a Component of an Integrated Mile-a-Minute Weed Management Program 45

revisited for at least 3 to 5 years, or until the MAM has been suppressed. In addition, a 

digital photo of the release site should be taken at the same time every year (late summer 

or early fall, before frost) for a visual record of changes in vegetation.

Combining biological control with other methods

Additional research is needed (and underway) to help us determine which MAM control 

methods are most compatible with the weevils. Although herbicides are not likely to 

have a direct detrimental effect on adult weevils, death of the plant will likely kill any 

developing larvae in the stems, and cause adults to disperse. High mowing of sites with 

weevils may make the site more conducive to weevil population growth by causing the 

plants to produce more of the tender terminals favored by the weevils, but this has not 

yet been proven.

As noted, competition with other plants is key in determining whether MAM can dominate a site. Weevil damage can cause MAM plants to become poorer competitors by 

reducing the number and size of seeds, shifting phenology of seed production to later in 

the year, and suppressing plant growth (Hough-Goldstein et al. 2008).

An important aspect of developing an integrated weed program is to assess the other 

vegetation that is present at a site dominated by MAM. Not much is gained if biological 

control agents suppress the target weed, only to have the target weed replaced by other 

nonnative invasive plant species. In some cases, control of MAM by whatever means 

should be followed or accompanied by planting of desirable vegetation.

Conclusion

The biological control program for P. perfoliata in the eastern U.S. was initiated in 1996, and a 

permit for release of the host-specific weevil, R. latipes, was obtained eight years later, in 2004. 

Although much remains to be learned, our first 4 years of experience suggest that this weevil 

will be very successful overall in suppressing the target weed. The weevil shows all the characteristics of a desirable biological control agent, including: a high reproductive rate, with three to 

four overlapping generations occurring each season; extreme host specificity; excellent dispersal 

capabilities; and the ability to suppress the target weed. Time will tell the extent to which it will 

control mile-a-minute weed in a variety of environments throughout the introduced range.

_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

 47

Appendices

Appendix A: Mile-a-minute weed monitoring protocol 

Revised, March 2008

Judy Hough-Goldstein, Department of Entomology & Wildlife Ecology, University of Delaware 

(jhough@udel.edu)

Introduction

Mile-a-minute weed (Persicaria perfoliata) is an annual Asian vine that invades a variety of 

habitats in the northeastern United States, including forested floodplains, streamside herbaceous wetlands, and upland forests. A biological control program targeting mile-a-minute 

weed (MAM) was initiated by the Forest Service in 1996, with field surveys and laboratory 

host-specificity tests conducted in China and subsequent testing under quarantine conditions in Delaware. A stem-boring weevil, Rhinoncomimus latipes Korotyaev, has been 

determined to be host-specific to MAM and a permit application for field release was approved in July 2004. The following guidelines are intended to help monitor the abundance 

of both MAM and the weevil, and assess the long-term impact of biological control. Ideally, 

monitoring should be initiated one or more years before biological control organisms are 

released, so that changes can be tracked pre- and post-release.

Mile-a-minute weed is a prickly, branching, viney annual plant that germinates in early 

spring, usually in April in the mid-Atlantic region. Vines grow rapidly, climbing over other 

plants, and attain lengths of 6 m or more. Flowers are inconspicuous, and iridescent blue 

berry-like achenes are produced, beginning in mid-summer and continuing until the plants 

are killed by frost in the fall. Seeds require a cold period before germinating. Many will germinate underneath established patches the following year, while others are spread by birds, 

mammals, water, and in the treads of shoes and tires. Mile-a-minute seeds can survive for up 

to 6 years in the seed bank.

Adult R. latipes are about 2 mm long, and are black, but once they start feeding they may 

be covered by an orange film derived from plant exudates. Adult weevils eat small holes in 

young leaves of P. perfoliata and lay eggs on leaves and stems. After hatching, larvae bore 

into the stem where they complete development, then exit the stem and drop to the soil for 

pupation. Development from egg to adult takes about 26 days under laboratory conditions. 

Weevils are very small, but can be observed directly in the field, especially at the ends of ter-
48 Appendices

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

minals (Fig. 42a). The pale yellow eggs have a characteristic peanut shape and are covered by 

a thin strip of fecal material (Fig. 42b); however they are difficult to spot in the field due to 

their very small size. Characteristic adult feeding holes (“shot holes” in leaves) are relatively 

easy to see (Fig. 42c). Larval emergence holes at plant nodes (near where ocreae encircle 

stems or where stems diverge) can sometimes be seen in the field (Fig. 42d).

Because of MAM’s rampant summer growth, and the fact that all reproduction is by seed 

(since plants die off, roots and all, following one or more hard frosts in the fall), we believe 

that plant populations are best assessed in the spring, when individual small plants can be 

counted in measured quadrats. Counts of overwintered weevils can be done at this time, 

too. Summer/fall assessments of weevil abundance and damage should be conducted, too, 

because populations will increase and spread during the summer. Summer and fall counts of 

seed production will help assess impacts on the plant population.

Site selection and quadrat placement

Selection

Select a weevil release/monitoring site that will be protected from other uses that could 

jeopardize insect establishment and continued monitoring, i.e. a site where the landowner will not attempt to control vegetation through mowing, herbicide use, etc. The study 

site should contain an ample population of MAM; however, ideally, native vegetation 

should be present so that control of MAM will result in the establishment of a moredesirable plant community.

Quadrat placement

Materials needed

One 0.5 m2 quadrat frame (see “Constructing a quadrat frame,” below), 80 pieces of 

0.5-inch or 0.75-inch plastic conduit pipe ~1 m long (to mark corners of 20 quadrats 

in each site), hammer, permanent marker, 50 or 100-m tape measure, GPS unit (if 

available), camera, work gloves

Within a single monitoring area (e.g. a state park), establish two 100-m-long transects, 

with similar habitat, vegetation, and mile-a-minute populations, but located approximately 500 m away from each other. Randomly assign one of these transects as the “release” transect, where weevils will eventually be released. The other transect will serve as 

Figure 42. a) Adult weevil; b) eggs with penny; c) adult feeding damage; d) larval node damage.
Appendices 49

_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

a non-release control site, at least until the weevils disperse into it. Along each transect, 

locate 10 quadrats, approximately 10 m apart. Permanently mark the position of each 

quadrat by placing the quadrat frame (Fig. 43) on the ground and hammering a 1-m long 

piece of conduit pipe into the ground at each inside corner. Using a permanent marker, 

write the quadrat number (R-1 through R-10 for the release transect and C-1 through 

C-10 for the control transect) on each corner pipe. Remove the frame but leave the pipes 

in the ground as markers for future reference. Move 10 meters along the transect and 

repeat the process until you have ten sets of quadrat markers in the ground. If 100-m 

long patches of MAM are not available, the 10 quadrats can be placed at random within 

the MAM infestation. Quadrat #5 will serve as the release point and should be located 

near the center. Make note of the approximate distance between quadrats on a sketch or 

map and attach it to Form 1 (below), along with GPS coordinates and/or landmarks to 

help to find the quadrats, later. A brightly colored flag placed in one of the corner pipes 

will also help when locating a quadrat. Identify permanent photo-points and take photographs of the study site, including one or more set of markers. Leave the markers in 

place until you’ve completed the study. Note: be sure to remove all the markers when 

you complete the study.

Establish the quadrats initially during the period of MAM germination and seedling 

emergence, making sure each quadrat has a MAM population. (Note, if other tearthumbs are present you may need to wait until plants have developed characteristic ocreae, 

encircling stems, before establishing quadrats).

Constructing a quadrat frame

Materials

One 10-foot length of 0.5- or 0.75-inch-diameter 

PVC or CPVC conduit pipe; four right-angle elbows 

of the same diameter; PVC or CPVC glue; hacksaw 

or pipe cutter; permanent marker; measuring stick or 

tape measure.

Assembly

The inside dimensions of the finished frame should 

measure 1 m by 0.5 m.

Using the hacksaw or pipe cutter, cut the pipe into four pieces; two pieces 1 m long, 

and two pieces 0.5 m long.

Glue an elbow to each end of one of the long pieces (a), taking care that the elbows 

are perfectly aligned with each other (share the same right-angle plane). Set this assembled piece aside; it will be the fourth side of the frame. (b) Glue the elbows on 

the remaining long piece and then glue a short piece into each elbow so as to form 

an open U-shaped frame. Using a permanent marker, mark 10-cm intervals on each 

side to assist in estimating percent cover and seedling numbers.

Do not glue assembly a

to assembly b

Glue

Glue

a

b

1m

0.5m

Figure 43. Diagram of a quadrat frame.
50 Appendices

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

Weevil release

Release approximately 200 or more adult weevils 

within quadrat #R-5. Carefully document all releases, including the date, numbers released and 

exact site of release.

Spring mile-a-minute survey (Form 1)

Materials needed

Ruler, Form 1 (make copies as needed), clipboard, 

pencils, camera, maps, work gloves, GPS unit, 

hand tally.)

Choose a date in spring after the main flush of 

mile-a-minute germination is complete (probably 

between April 15 and May 15), but before vines 

have become too dense to count. Ideally, MAM 

stems should be 15 – 30 cm (6” – 12”) tall. Measure 

the height of an average stem (or a range of heights 

if there is much variation) and note it on the survey 

form. Slide the quadrat frame in place around the four corners, and survey each quadrat for 

the following:

•	 Number of weevils (if released in previous years, or where weevils may have spread on 

their own). Adult weevils tend to drop from plants when disturbed, so approach each 

quadrat site carefully. First count and record all adult weevils that can be seen on plants 

within the approximate confines of the quadrat. Weevils will generally be on MAM terminals or foliage, often near characteristic “shot hole” feeding damage.

Figure 44. Percent of defoliation. Note, examples of damage up to 40% are shown, but damage up 

to 100% can be estimated.

We maintain a data base of all North American releases, so please 

inform our lab of any new releases as 

soon as they occur. Please send the following information to Dr. Judith HoughGoldstein at jhough@udel.edu: 

•	Date of release

•	Number released

•	State

•	County

•	Location (park, refuge, or municipality)

•	Description of exact site

•	GPS coordinates, if available

Also, please let us know where you obtained the weevils (e.g. Philip Alampi 

Laboratory, or from an established field 

site), and send us copies of all monitoring forms (see below) at the end of the 

season.
Appendices 51

_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

•	 Total number of mile-a-minute seedlings present in the quadrat. Use a tally counter for 

accuracy. If too many are present to count, you may count the number in half or a quarter of the quadrat and multiply by 2 or 4 to arrive at a reasonable estimate within the 

entire quadrat; however, if you do this, to avoid errors note it on Form 1 under “Comments” (last column).

•	 Number of stems of other plant species. Identify as many other species as possible, especially those that are most abundant, and note these on the form under “Comments.” 

•	 Percent cover. Standing over the frame, look straight down and estimate how much of the 

quadrat is covered by mile-a-minute foliage and vines, and how much is covered by all 

other vegetation (these estimates may total >100%, due to layering). 

•	 Note presence or absence of “shot holes”, the characteristic damage of feeding weevils.

Summer/fall assessment of weevil abundance, plant damage, and 

seed production

Materials needed: Form 2 (make copies as needed), clipboard, pencils, work gloves, (optional, GPS unit, hand tally). Once each month following the seedling counts (or weevil release) 

until plants senesce, return to each quadrat site and survey for the following within each 

quadrat and record your findings on Form 2 (below) (Note: if substantial mile-a-minute 

growth has occurred, it may be necessary to search out, locate, and cut a path to, each quadrat the week before the samples are taken): 

•	 Number of weevils. Carefully approach each quadrat site and first count and record 

all adult weevils that can be seen on plants within the approximate confines of the 

quadrat.

•	 Percent defoliation. Scan the foliage for “shot holes” in leaves, the characteristic damage caused by feeding weevils, and assess the percentage of leaf area removed from 

mile-a-minute foliage within the approximate confines of the quadrat (see Fig. 44, 

above). If insects other than the weevil are present, e.g., Japanese beetles, and appear 

to be damaging the foliage note this under “Comments” on Form 2.

•	 Node damage (yes or no). Look closely at stems where adult weevil feeding damage 

is evident, and note presence or absence of node damage, where larvae have fed in 

stems or emerged for pupation.

•	 Percent mile-a-minute cover. Standing over the frame, look straight down and estimate how much of the quadrat is covered by green (not senescent) mile-a-minute 

foliage and vines.

•	 Number of fruiting terminals. Once seed clusters have formed, count the number 

of mature (containing at least one blue or purple seed) and immature (all green) seed 

clusters within each quadrat. 
52 Appendices Biology and Biological

Control of Mile-a-Minute Weed ________________________________________

Quadrat 

number

Number of 

weevils 

(count first)

Number of stems 

originating in 

quadrat

Percent cover 

in quadrat

Weevil 

feeding

damage

Comments

(Other plants present in the quadrat, etc.)

MAM Other MAM Other Yes No

R-1R-2R-3R-4R-5R-6R-7R-8R-9

R10

C-1C-2C-3C-4C-5C-6C-7C-8C-9

C-10

Form 1. Spring mile-a-minute survey. To be conducted after flush of MAM germination, probably between April 15 and May 15, but before vines become too dense,when stems are between 15 and 30 cm (6 to 12”) long.SiteDateApproximate length of MAM stemsPerson(s) conducting survey

This form is available as a Microsoft ®Excel® spreadsheet. Contact Dr. Judith Hough-Goldstein, jhough@udel.edu.
Appendices 53

_________________________________________ Biology and Biological Control of Mile-a-Minute Weed Quadrat number Number of weevils (count first) Percent of leaf area removed by insects Node damage Percent MAM cover in quadrat Number of fruiting terminals* Comments (Other plants present in the quadrat, etc.) Yes No Mature Immat. R-1 R-2 R-3 R-4 R-5 R-6 R-7 R-8 R-9 R10 C-1 C-2 C-3 C-4 C-5 C-6 C-7 C-8 C-9 C-10 Form 2. Summer/fall weevil and plant monitoring. To be conducted monthly. Site Date Person(s) conducting survey *Mature fruiting terminals have at least one blue/purple seed; immature terminals have buds or seeds that are all green. This form is available as a Microsoft ®Excel® spreadsheet. Contact Dr. Judith Hough-Goldstein, jhough@udel.edu.
54 Appendices

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

Appendix B: Mile-a-minute weed quick monitoring protocol, 

July 2008

Judy Hough-Goldstein, Dept. Entomology & Wildlife Ecology, University of Delaware 

(jhough@udel.edu)

Not all land managers have the labor or time to follow the complete monitoring protocol. 

Therefore, we developed an alternative “quick” protocol:

•	 Physically mark the location where weevils are released, using a wood, metal or plastic 

stake with flagging tape.

•	 Determine the latitude and longitude of the release point using GPS or Google® Earth.

•	 Record the date and number of weevils that are released, along with a descriptive label 

(e.g. Longwood-1) and detailed description of the location so it can be found again even if 

the physical marker is lost.

•	 Estimate the percent cover of mile-a-minute (MAM) in the area immediately surrounding 

the release point (within a circle of ~1-meter radius), to the nearest 5%.

•	 Note what other plants are dominant within that circle.

•	 Take a digital photo of the release site and return every year at the same date (late summer 

or early fall, before frost) to take another photo from the same location (vantage point). 

Include the release plot and surrounding area in the photo. Note the date and if possible 

include a noticeable landmark in the photo.

Go back to the release point three times each year (Spring, Summer, and Fall), and record the 

following:

•	 Date, location.

•	 Presence and extent of weevil feeding damage on MAM (none, low, medium, or high damage; see form for description of categories).

•	 Number of weevils (if any) found within ~1-meter radius of the release point; search and 

count for at least 2 minutes.

•	 Presence of node damage on MAM, indicating egg production and larval tunneling.
Appendices 55

_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

•	 Estimated percent cover of MAM in the area immediately surrounding the release point 

(within a circle of ~1-meter radius), to the nearest 5%.

•	 Other plants that are present within that circle.

•	 If MAM and/or weevils or damage are not present within the immediate area of the release, search the surrounding area and note the presence or absence and extent of MAM 

and weevils or feeding damage.

Images of MAM, weevils, feeding and node damage can be found at

http://ag.udel.edu/enwc/research/biocontrol/index.htm

Please record your results on the survey form (Form 3, below) and send it to:

Dr. Judy Hough-Goldstein

Dept. of Entomology & Wildlife Ecology

Townsend Hall Rm. 250

531 South College Ave.

Newark DE 19716-2160

jhough@udel.edu 

302-831-8889 fax
56 Appendices

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

Form 3: Mile-a-Minute Quick Monitoring Survey

Mile-a-Minute Quick Monitoring Survey

(Survey to be conducted at time of weevil release and three times per year thereafter, once 

each in spring, summer, and fall, until MAM is suppressed [3 – 5 years])

Site location (descriptive label):______________________________________________________________

Date: _________________________

Person(s) conducting survey: _______________________________________________________________

Phone # or e-mail of person conducting survey or supervisor: ___________________________________

At time of release:

Physically mark the site of release, and attach a map/sketch and description of the release site, with 

enough detail that the site can be found again even if the physical marker is lost. 

Site latitude and longitude: _________________________________________________________________

Number of weevils released: _______________________________________________________________

Estimated % cover of MAM (to nearest 5%) within ~1-meter radius of release: _____________________

Other plants dominant within ~1-meter radius of release: _______________________________________

________________________________________________________________________________________

When site is revisited:

Estimated % cover of MAM (to nearest 5%) within ~1 m radius of release: ________________________

Weevil feeding damage on MAM at release site (circle one): none, low, medium, high

(low = holes in a few scattered leaves; medium = holes in many leaves; high = extensive damage on 

most leaves)

Number of weevils within ~1-meter radius of release point (2-minute [minimum] count): ____________

(Note: Typically, counts are low in the year of release and the following year.)

Visible node damage on MAM within ~1-meter radius of release point (yes or no): __________________

Other plants dominant within ~1-meter radius of release point: __________________________________

________________________________________________________________________________________

If MAM and/or weevils are not present within ~1-meter radius of release point, search the 

surrounding area and note presence and extent of MAM, weevils, and weevil feeding damage:_________

________________________________________________________________________________________

Comments:
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

 57

Glossary

abdomen The last of the three insect body regions; usually contains 

the digestive and reproductive organs.

achene A small, dry, indehiscent fruit with a single seed.

alternate Leaves that are arranged singly at each node along a stem.

annual A plant that flowers and dies within a period of one year 

from germination.

apical dominance Influence exerted by a terminal bud in suppressing the 

growth of lateral buds.

aspirator An apparatus used to suck insects into a collection container. 

beetle A member of the very large and variable insect order 

Coleoptera; adults have hardened or leathery forewings 

(elytra) while larvae may be grub-like or mobile; beetles 

exhibit complete metamorphosis. 

biological control The reduction in the abundance of a pest through intentional use of its natural enemies (predators, parasitoids, 

and pathogens); also called “biocontrol.” 

biological control agent A natural enemy of a target pest used in biological control efforts. 

chemical weed control Weed control strategies employing herbicides.

choice test A test of host specificity in which the potential biological control agents are presented with a combination of 

test-plant species along with the target weed, and their 

oviposition or feeding is recorded.
58 Glossary

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

classical biological control A biological control strategy employing the release of 

a pest’s natural enemies imported from another region; 

typically directed against exotic pests, it uses natural 

enemies from areas where the pest is native. 

cold stratification A period of moist cold required for some seeds before 

they will germinate. 

competition Negative interactions between individuals of the same 

or different species that utilize the same resource(s); if 

the resource is in short supply, one individual or species 

may survive and increase in number at the expense of the 

other(s). 

complete metamorphosis A type of insect development characterized by immature 

stages (larvae and pupae) that look quite different from 

the adults, and typically live in different habitats, eat different foods, and exhibit different behaviors than do the 

adults. 

community A naturally occurring group of different species of organisms that live together and interact as a more or less selfcontained “unit.” 

cover The portion of the vegetative canopy in a fixed area attributable to an individual or a single plant species. 

cultural methods Weed control methods that modify the plant’s environment, such as adding or removing shade or fostering 

competition with other plants

defoliation The loss of foliage, often due to insect feeding. 

defoliator An organism, usually an insect, that consumes plant foliage. 

density Number of individuals per unit area. 

dispersal The spread of animals and plants from any point; the 

redistribution of plant seeds, fungal spores, or insect eggs, 

larvae, and adults. 

dormant In a state of temporarily reduced metabolic activity. 

emergence Act of adult insect leaving the pupal case or reappearing 

after overwintering.

eradicate Total elimination of an organism from an area.

excelsior Long, thin wood shavings used for packing.
Glossary 59

_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

exoskeleton A hard outer structure, such as the shell of an insect or 

crustacean, that provides protection or support for the 

organism. 

exotic Not native. 

FHTET Forest Health Technology Enterprise Team, a division of 

the USDA Forest Service

field insectary An area where host plants or animals are abundant and 

biological control agents are released and propagated 

with or without additional human manipulation. 

forb A herbaceous plant that is not a grass nor grass-like in 

form. 

frass The excrement produced by insects, containing feces and 

undigested plant material 

genus (pl. genera) A taxonomic category ranking below a family and above 

a species and generally consisting of a group of species 

exhibiting similar characteristics. In taxonomic nomenclature the genus name is used, either alone or followed 

by a Latin adjective or epithet, to form the name of a species.

herbicide A chemical substance used to destroy or inhibit the 

growth of plants, especially weeds.

herbivory Feeding on plants.

host The plant or animal on which an organism feeds; the organism utilized by a parasitoid; a plant or animal susceptible to attack by a pathogen. 

host range The different host species that may be utilized by a plantor animal-feeding organism. 

host specificity The dietary restriction of an organism to a single or 

limited food (for herbivores: the number of plant species 

accepted as food; the highly-evolved, often obligatory association between an insect and its host(s); the degree to 

which an organism is restricted to a particular number of 

plant or animal hosts.) 

insect A small arthropod animal that, as an adult, normally has 

six legs, three distinct body regions, one pair of antennae, 

and one or two pairs of wings. 

instar Period or stage between successive molts in a insect larva. 
60 Glossary

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

integrated weed management A system for planning and implementing a program to 

contain or control an undesirable plant species or group 

of species, using all available methods and a thorough 

knowledge of pest biology. 

invasive plant An aggressive and dominant plant, likely to colonize 

and become established in new habitats; usually refers to 

weeds. 

lamina The expanded portion, or blade, of a leaf or petal.

larva (pl. larvae) Immature insect stage between the egg and pupa. 

mass rearing The mass production of a natural enemy.

mechanical weed control Mechanical methods that employ physical means to remove or control weeds, including activities such as hand 

pulling, hoeing, tilling, mulching, burning, and mowing. 

metamorphosis The change from one life stage to another in insects, such 

as from larva to pupa. 

molt The process by which insects and other arthropods shed 

their exoskeleton (“skin”) as they grow and develop; 

among insects, molting is typically restricted to larval or 

nymphal stages. 

monoculture An area vegetated by a single plant species. 

natural enemies The parasites, predators, pathogens, and other antagonists associated with a species of animal or plant that 

cause debility or mortality.

no-choice test A test of host-specificity in which the potential biological 

control agent is presented with a single, non-target testplant species at a time. Feeding, development, survival 

rate and/or oviposition rates are recorded and compared 

to those on the target weed.

node The position on a stem where leaves or branches originate; also known as a “joint.”

non-target Not being the target of a control method, e.g., not a desired host or food source for a biological control agent. 

ocrea (pl. ocreae) Fused stipules that surround the stem at each leaf node; 

in mile-a-minute weed the ocreae flare widely into a saucer shape. 

oligophagous Feeding on a few (usually related) different types of 

plants or prey.
Glossary 61

_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

oviposit To lay or deposit eggs. 

PABIL Phillip Alampi Beneficial Insect Laboratory, a New 

Jersey Department of Agriculature facility for rearing 

biocontrol agents, located in West Trenton, NJ. 

perennial A plant living more than two years. 

petiole A leaf stalk.

physiological host range All plant species that support feeding, development, and 

reproduction of a particular insect species, when tested 

under laboratory conditions.

phytophagous insect An insect that feeds on plants.

polyphagous insect An insect that feeds on many types of plants or prey.

post-emergent herbicide An herbicide that controls plants via uptake of chemical 

through the plant foliage or stems.

pre-emergent herbicide An herbicide that controls plants before they emerge 

from the ground by injuring the plant as the seed germinates.

pupa (pl. pupae) (v. pupate) Non-feeding, inactive stage between the larva and adult 

in insects with complete metamorphosis. 

phylogenetic Relating to or based on evolutionary development or history.

quadrat A specific area used to sample vegetation (e.g., 1 square 

meter, or 1m2

). 

radicle The first part of a seedling (a growing plant embryo) 

to emerge from the seed during the process of germination; the embryonic root of the plant.

scarification Cutting or softening the hard wall of a seed to break seed 

dormancy.

seed bank An accumulation in the soil of long-lived seeds, which 

can potentially germinate many years after they were 

produced.

species A fundamental category of taxonomic classification, 

ranking below a genus or subgenus and consisting of 

related organisms capable of interbreeding.
62 Glossary

Biology and Biological Control of Mile-a-Minute Weed ________________________________________

surfactant A compound that increases the effectiveness of an herbicide by increasing the adherence of the herbicide mixture 

to the leaf surface, reducing the surface tension of the 

mixture so it spreads over more of the leaf and aiding 

penetration of the waxy outer cuticle of the leaf.

TAG Technical Advisory Group for Biological Control Agents 

of Weeds 

taxonomy The classification of organisms in an ordered system 

that indicates natural relationships. The science, laws, or 

principles of classification; systematics. 

terminal The growing tip of a mile-a-minute weed vine or vine 

branch; may eventually develop into a flower cluster.

thorax Body region of an insect, behind the head, bearing the 

legs and wings. 

transect A straight line or path through an area. 

USDA-APHIS- PPQ United States Department of Agriculture- Animal and 

Plant Health Inspection Service- Plant Protection and 

Quarantine. 

vegetative reproduction Reproduction in plants other than by seeds, such as from 

rhizomes, stolons, and from nodes on lateral, often creeping, roots. 

viability The proportion of propagules (e.g., seeds) that are alive 

and can germinate. 

weevil A type of plant-eating beetle, the adults having distinct 

snouts of variable lengths.
_________________________________________ Biology and Biological Control of Mile-a-Minute Weed

 63

References

Introduction

Bourchier, R., R. Hansen, R. Lym, A. Norton, D. Olson, C.B. Randall, M.Schwarzländer, 

and L. Skinner. 2006. Biology and biological control of leafy spurge. USDA Forest Service 

Publication FHTET–2005–07.

Rejmánek, M., and J. M. Randall. 1994. Invasive alien plants in California: 1993 summary 

and comparison with other areas in North America. Madroño 41 (3): 161–177.

Wilson, L. M., M. Schwarzländer, B. Blossey, and C. B. Randall. 2004. Biology and Biological Control of Purple Loosestrife. USDA Forest Service Publication FHTET–2004–12.

Wu, Y., R. Reardon, and Ding Jian-qing. 2002. Mile-a-minute weed. In: Van Driesche, R., S. 

Lyon, B. Blossey, M. Hoddle, and R. Reardon. Biological Control of Invasive Plants in the 

Eastern United States. USDA Forest Service Publication FHTET–2002–04.

Chapter 1: Getting to Know Mile-a-Minute Weed

Colpetzer, K. and J. Hough-Goldstein. 2004. A rapid germination protocol for mile-a-minute weed, Polygonum perfoliatum L. Seed Science and Technology 32: 749–757.

Hinds, H.R. and C.C. Freeman. 2005. Persicaria. In Flora of North America, v. 5. Polygonaceae. http://www.eFloras.org.

Moul, E.T. 1948. A dangerous weedy Polygonum in Pennsylvania. Rhodora 50: 64–66.

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deer: implications for long-distance dispersal, invasion, and migration of plants in eastern 

North America. Oecologia 139: 35–44.

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leading to the formation of a management policy. Ph.D. Dissertation, George Mason University, Fairfax, Virginia.

Shuppert, D.A. 2001. Assessment of genetic variation among populations of Polygonum perfoliatum using RAPD markers. MS thesis, Towson University, Towson MD.
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Van Clef, M. and E. W. Stiles. 2001. Seed longevity in three pairs of native and non-native 

congeners: assessing invasive potential. Northeastern Naturalist 8: 301–310.

Vellend, M. 2002. A Pest and an Invader: White-tailed Deer (Odocoileus virginianus

Zimm.) as a Seed Dispersal Agent for Honeysuckle Shrubs (Lonicera L.). Natural Areas 

Journal 22: 230–234.

Chapter 2: Mile-a-Minute Weed Biological Control Agents 

Colpetzer, K., J. Hough-Goldstein, J. Ding, and W. Fu. 2004. Host specificity of the Asian 

weevil, Rhinoncomimus latipes Korotyaev (Coleoptera: Curculionidae), a potential biological control agent of mile-a-minute weed, Polygonum perfoliatum L. (Polygonales: Polygonaceae). Biological Control 30: 511–522.

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potential insect biocontrol agents of mile-a-minute weed, Polygonum perfoliatum L., in 

Eastern USA. Biological Control 30: 487–495.

Fredericks, J.G. III. 2001. A survey of insect herbivores associated with Polygonum perfoliatum L. (mile-a-minute weed) and comparisons of leaf damage and insect diversity between 

recently established and mature populations. MS Thesis. University of Delaware, Newark 

DE.

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fauna of mile-a-minute weed, Persicaria perfoliata (Polygonaceae) in Japan. Florida Entomologist 91: 319–323.

Mountain, W.L. 1989. Mile-a-minute (Polygonum perfoliatum L.) update – distribution, biology, and control suggestions. Regulatory Horticulture 15: 21–24.

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Price, D.L., J. Hough-Goldstein, and M.T. Smith. 2003. Biology, rearing, and preliminary 

evaluation of host range of two potential biological control agents for mile-a-minute weed, 

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Triplehorn, C.A. and N.F. Johnson. 2005. Borror and DeLong’s Introduction to the Study 

of Insects, 7th ed. Thomson Brooks/Cole, Belmont CA.

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Chapter 3: Rhinoncomimus latipes in the United States

Hough-Goldstein, J., M. Schiff, E. Lake, and B. Butterworth. 2008. Impact of the biological 

control agent Rhinoncomimus latipes (Coleoptera: Curculionidae) on mile-a-minute weed, 

Persicaria perfoliata, in field cages. Biological Control 46: 417–423.

Lake, E.C. 2007. Dispersal, establishment, and impact of the mile-a-minute weevil, Rhinoncomimus latipes Korotyaev (Coleoptera: Curculionidae): a two-year study in Southeastern 

Pennsylvania. M.S. Thesis, University of Delaware, Newark, DE.
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Chapter 4: Biological Control as a Component of an Integrated 

Mile-a-Minute Weed Management Program

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Science 50: 273–280.

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gin trash. Communications in Soil Science and Plant Analysis 32:491–507.

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control agent Rhinoncomimus latipes (Coleoptera: Curculionidae) on mile-a-minute weed, 

Persicaria perfoliata, in field cages. Biological Control 46: 417–423.

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