State DOT Listings of Their Top Priority Invasive
Species
Asiatic/Oriental
bittersweet |
CT, NH, NC,
RI |
Australian pine |
FL |
Autumn olive |
CT, IN |
Bamboo |
SC |
Branched broomrape |
TX |
Brazilian pepper |
FL |
Broomsedge |
NC |
Bush honeysuckle |
KY, NH |
Callery pear |
AR |
Camelthorn |
AZ |
Canada thistle |
CO, IL, IN,
IA, MD, MN, NE, OH, SD, WV, WI, WY |
Cape ivy |
CA |
| Chinese bush clover |
KS |
| Chinese Clematis |
CO |
| Cogongrass |
FL, LA, MS |
| Common buckthorn |
MN |
Common or cutleaf
teasels |
IL, IA, MO |
Dalmation toadflax |
AZ, WA |
Diffuse knapweed |
CO, WY |
Empress tree |
VA |
Field Bindweed |
KS, NE, WI |
French broom |
CA |
Giant hogweed |
NY |
Giant reed |
CA, TX |
Gorse |
OR |
Guinea Grass |
HI |
Hairy whitetop
/ Hoary cress |
NM, NV |
Hydrilla |
FL |
Italian ryegrass |
MS |
Itchgrass |
LA |
Ivy gourd |
HI |
Japanese Knotweed |
CT, KY, NH,
NY, NC, OR, RI |
Johnsongrass |
AR, IL, IN,
KS, KY, MD, MS, MO, OH, SC, TX, VA |
Jointed goatgrass |
NM |
Knapweeds |
NM, WA |
Knotweeds |
WA, WV |
Burning bush
(Kochia) |
WA |
Kudzu |
AR, FL, IL,
MS, MO, NC, SC, TX, VA, WV |
Leafy spurge |
CO, IA, MN,
NE, SD, WI |
Old World climbing
fern (Lygodium) |
FL |
Maile pilau |
HI |
Mile-a-minute |
MD |
Multiflora rose |
KS, NH, WV |
Musk thistle |
IA, KS, KY,
MO, OH, WY |
Mysore thorn |
HI |
Peruvian watergrass |
LA |
Phragmites /
Common reed |
CT, IN, MD,
NY |
Poison hemlock |
KY, OH |
Purple loosestrife |
CT, IL, IN,
MN, NY, OH, RI |
Reed canarygrass |
OR |
Russian knapweed |
AZ, NV, WY |
Russian olive |
RI |
Russian thistle |
OR |
Ryegrass |
SC |
Salt cedar |
CO, NE, NM,
TX |
Shoebutton |
HI |
Spotted knapweed |
MN, MO, NE,
NV, OR, WY |
Tall whitetop |
NV |
Tallow trees |
LA |
Thistles spp. |
AZ, AR, CA,
NV, NM, SC |
Tree of heaven Ailanthus
altissima |
MD, RI, VA,
WV |
Tropical soda
apple |
FL |
Trumpet vine |
VA |
Water hyacinth |
FL |
Wild parsnip |
IA |
Yellow starthistle |
WA |
Africanized
bees |
AZ |
Bagworm |
MD |
Boll weevil |
NC |
Dutch elm disease |
MN |
Eastern tent
caterpillar |
MD |
Emerald ash
borer |
OH |
Grasshoppers |
MN |
Gypsy moth |
MD, NH, NC |
Eucalyptus redgum
lerp psyllid |
CA |
Mimosa webworm |
MD |
Oak wilt |
MN, TX |
Pine bark beetle |
MN |
Red imported
fire ants |
AZ, LA, NC,
SC, TX |
Sudden oak death |
CA |
West Nile virus |
AZ, NM, RI,
VA, WA |
Zebra mussel |
AR, NY |
Lists of Top Priority Species by Scientific and
Common Names, with Sources for Further Information
Asiatic/Oriental
bittersweet |
Celastrus orbiculatus |
Australian pine |
Casuarina equisetifolia |
Autumn olive,
Elaeagnus, Oleaster, Japanese Silverberry |
Elaeagnus umbellata |
Bamboo |
Family Graminae |
Branched broomrape |
Orobanche ramosa |
Brazilian pepper |
Schinus terebinthifolius |
Broomsedge,
Beard grass |
Andropogon
spp. |
Burning bush,
Fireweed, Summer cypress |
Kochia scoparia
(L.) Roth |
Bush honeysuckle |
certain Lonicera
spp. |
Callery pear |
Pyrus calleryana |
Camelthorn |
Alhagi maurorum
Medik. |
Canada thistle,
Californian thistle, Canadian thistle, creeping
thistle, field thistle, corn thistle, perennial
thistle, field thistle |
Cirsium arvense
(L.) Scop |
Cape ivy or
German ivy |
Delairea odorata |
Chinese bush
clover |
Lespedeza cuneata
(Dumont) G. Don |
Chinese Clematis,
Oriental virginsbower |
Clematis orientalis
L. |
Cogongrass |
Imperata cylindrica
(L.) Beauv. |
Common buckthorn,
European buckthorn |
Rhamnus cathartica
L. |
Common teasel,
wild teasel, Fuller's teasel, venuscup teasel |
Dipsacus fullonum
L. |
Cutleaf teasel |
Dipsacus laciniatus
L. |
Dalmatian toadflax,
broadleaf toadflax |
Linaria dalmatica
(L.) P. Mill. |
Diffuse knapweed,
white knapweed, spreading knapweed, tumble knapweed |
Centaurea diffusa
Lam. |
Empress tree,
Princess tree, Royal paulownia |
Paulownia tomentosa
(Thunb.) Sieb. & Zucc. ex Steud. |
Field bindweed,
Creeping Jenny |
Convolvulus
arvensis L. |
French broom |
Genista monspessulana
(L.) L. Johnson |
Giant hogweed,
cartwheel-flower |
Heracleum mantegazzianum |
Giant reed,
Spanish reed |
Arundo donax
L. |
Gorse |
Ulex L. spp. |
Guinea grass |
Urochloa maxima
(Jacq.) R. Webster |
Hairy whitetop,
Hoary cress, Globe-podded hoary cress, Ball cress,
White-top lens, Peppergrass |
Cardaria draba
(L.) Desv. |
Hydrilla, Waterthyme |
Hydrilla verticillata
(L. f.) Royle |
Italian ryegrass |
Lolium multiflorum
Lam. |
Itchgrass |
Rottboellia
cochinchinensis (Lour.) W.D.Clayton |
Ivy gourd |
Coccinia grandis
(L.) Voigt |
Japanese knotweed,
fleeceflower, Mexican bamboo, huzhang |
Polygonum cuspidatum
Siebold & Zucc. Sacchalineuse, Fallopia japonica,
Reynotria jap. |
Johnsongrass,
Johnson grass, Aleppo grass, Aleppo milletgrass |
Sorghum halepense
(L.) Pers. |
Jointed goatgrass |
Aegilops cylindrica
Host |
Knapweeds |
Centaurea spp. |
Knotweeds |
Polygonum spp. |
Kudzu |
Pueraria montana
(Lour.) Merr. var. lobata (Willd.) Maesen & S.
M. Almeida |
Leafy spurge |
Euphorbia esula
L. |
Old World climbing
fern |
Lygodium microphyllum |
Maile pilau,
stinkvine |
Paederia foetida
L. |
Mile-a-minute
weed, Chinese tearthumb |
Polygonum perfoliatum
L. |
Multiflora rose,
baby rose, Japanese rose, seven-sisters rose, rambler
rose, multiflowered rose |
Rosa multiflora
Thunb. |
Musk thistle,
Nodding thistle |
Carduus nutans
L. |
Mysore thorn,
Shoofly |
Caesalpinia
decapetala |
Peruvian watergrass |
Luziola peruviana
Juss. ex J.F. Gmel. |
Common reed |
Phragmites
australis (Cav.) Trin. ex Steudel |
Slipper flower,
Redbird flower |
Pedilanthus
tithymaloides |
Long-stalked
Phyllanthus |
Phyllanthus
tenellus |
Poison hemlock |
Conium maculatum |
Purple loosestrife,
spiked loosestrife |
Lythrum salicaria
L. |
Reed canarygrass |
Phalaris arundinacea
L. |
Russian knapweed,
Turestan thistle, Creeping knapweed, Mountain Bluet,
Russian cornflower, hardheads |
Acroptilon
repens (L.) DC. |
Russian olive,
oleaster |
Elaeagnus angustifolia
(L.) |
Prickly Russian
thistle |
Salsola tragus
L. |
Ryegrass |
Lolium spp. |
Saltcedar, salt
cedar, tamarisk |
Tamarix L.
spp. |
Shoebutton |
Ardisia elliptica
Thunb. |
Spotted knapweed |
Centaurea biebersteinii
DC. (syn. Centaurea maculosa) |
Perennial peppergrass,
slender perennial peppercress, broadleaf pepperweed,
tall whitetop, giant white weed, iron weed |
Lepidium latifolium
L. |
Tallowtree,
Chinese tallow tree |
Triadica sebifera
(L.) Small, Sapium sebiferum (L.) Roxb. |
Tree-of-heaven,
China-sumac, varnishtree |
Ailanthus altissima
(Mill.) Swingle |
Tropical soda
apple |
Solanum viarum
Dunal |
Trumpet vine |
Campsis radicans |
Common water-hyacinth,
floating water hyacinth, jacinthe d'eau, Wasserhyazinthe,
jacinto-aquatico, lechuguilla |
Eichhornia
crassipes |
Wild parsnip |
Pastinaca sativa
L. |
Yellow star
thistle, geeldissel, golden star thistle, St. Barnaby's
thistle, yellow centaury, yellow cockspur |
Centaurea solstitialis
L. |
Africanized
honeybee, African honey bee, Killer bees |
Apis mellifera
scutellata Lepeletier |
Bagworm |
Thyridopteryx
ephemeraeformis (Haworth) |
Boll weevil |
Anthonomus
grandis Boheman |
Dutch elm disease
causal agent |
Ophiostoma
ulmi |
Eastern tent
caterpillar |
Malacosoma
americanum (Fabricius) |
Emerald ash
borer |
Agrilus planipennis
(Fairmaire) |
Grasshoppers |
Melanoplus
spp. |
Gypsy moth,
European gypsy moth |
Lymantria dispar
Linnaeus |
Eucalyptus redgum
lerp psyllid |
Glycaspis brimblecombei
Moore |
Mimosa webworm |
Homadaula anisocentra
(Meyric) |
Oak wilt causal
agent |
Ceratocystis
fagacearum |
Pine bark beetles |
Family Scolytidae |
Red imported
fire ant |
Solenopsis
invicta Buren |
Sudden oak death
casual agent |
Phytophthora
ramorum |
West Nile virus |
Flavivirus |
Zebra mussel |
Dreissena polymorpha
(Pallas, 1771) |
Resources
Sample DOT Invasive Species Inventory Forms
View
Sample Form [ pdf / 8kb]
An Overview of Common IRVM or IVM Steps
One of the best overviews of IVM plan components
is a series of technical bulletins developed as
a resource for vegetation managers seeking practical
information on effective, environmentally sound methods
for managing invasive species. The series was
authored by the Bio-Integral Resource Center (BIRC)
through a U.S. EPA grant. These bulletins have
been published on the Internet at IPM
Access through a separate EPA grant as a result
of the EPA's interest in this type of information being
made freely available to a wider audience. The
following sections, addressing the principle components
of IVM programs, are adapted from that resource:
- Gathering background information and conducting
weed inventories.
- Setting management objectives.
- Establishing monitoring programs to inventory weed
growth stages, locations, and acreage infested.
- Setting treatment action levels and treatment thresholds
to determine if treatment is necessary.
- Using weed prevention measures and revegetation
in your management plan.
- Applying effective, least-toxic management methods.
- Educating the public.
- Evaluating the program.
The goal of an IVM or IRVM program is to keep noxious
weed populations low enough to prevent unacceptable
spread, damage, or annoyance, and to encourage desirable
vegetation to permanently replace the weeds. Treatment
occurs only when monitoring indicates thresholds have
been reached and treatment is necessary. Several methods
are selected from educational, biological, cultural,
manual, mechanical, and least-toxic chemical control
tactics, and then integrated into a treatment program.
IVM emphasizes revegetation with desirable plant species
as well as other actions that will prevent future weed
infestations. When applied appropriately, the
IVM process results in improved management, lower cost,
greater ease of maintenance, and lower environmental
impacts from control activities.
Gathering Background Information on the Target Invasives
Gathering as much information as possible about the
biology and growth patterns of the target weed can
assist and help direct management. Still other
useful information can only be gathered on site and
will be specific to your own problem situation. Information
that will help staff to identify the target species
may include:
- Common and scientific name
- Picture (as a young plant and in full seed/flower) ― note
if easily confused with others
- Annual or perennial
- Growth form and habits
- How tall the weed grows
- Timing of flowering or seed setting, which varies
with latitude
- Distribution, geographical origin, and site preferences
Life cycle and lifespan information also helps determine
proper treatment methods. Perennial weeds store nutrients
underground and can access these reserves to resprout
repeatedly. Maintenance staff may find the following
valuable in determining appropriate treatment:
- How does the weed reproduce? If the weed
spreads by seeds, note the flowering time since control
measures will usually occur before the flowers produce
seeds to prevent another seedcrop. Are
a large number of seeds produced?
- What is the mechanism(s) of seed dispersal and
how can it be reduced?
Also important are any special challenges the species
presents in attempting to manage or control it. Knowing
such challenges helps the design, construction, or
maintenance manager to plan accordingly. For
example, all invasives tend to have seeds that remain
viable in the soil for many years
- Can one small fragment regenerate an entire plant?
- Is the target weed found in sensitive areas such
as wetlands or streamsides where treatment methods
are limited?
- Is the weed resistant to certain types of control
methods?
- Who are the people and the agencies that are concerned
about this weed?
- What is the natural history of the site you are
trying to manage (the soil type, amount of rainfall,
species of animals and competitive vegetation present)?
- How is the land being used (present and future
plans) and what is the history of land use?
- What is the history of weed control on the site?
- Is this a recent invasion or an old problem?
Understand the Damage or Potential Threat
The damage caused to native plant communities by
invasive species is extensive. Not only do weeds directly
compete with native species for space, light, moisture,
and nutrients, but they also have the ability to physically
alter the structure or the nutrient cycling of a system,
disrupting natural ecosystem function to which native
communities are adapted.
Set Management Objectives
When setting management objectives, the weed manager
will need to balance the resources available with the
requirements of the law. The following questions
may help in clarifying objectives:
- What are the legal requirements?
- What are the available resources (money, people,
time)?
- Which control strategies are best suited to the
weed I am trying to manage and the area in which it
occurs?
- What is the availability of biological control
agents or grazing animals?
- What are the environmental considerations?
- What other people or agencies do I need to collaborate
with?
- What kind of follow-up preventive measures will
need to be implemented?
- What kind of public education is needed?
- What is the desired level of control (see below)?
Can this level be sustained by my resources?
Levels of potential control include:
- Containment - keeping an established population
of the weed in check so that the area infested by
the weed does not increase. This strategy can be employed
against newly-invading weeds or well-established species.
It is especially useful when time and money are in
short supply or when the infestation is very large.
- Reduction - reducing the area covered by a weed,
or reducing the dominance of that weed. This strategy
can also be used against new or established weeds,
but it requires more resources and more time than
containment.
- Eradication - completely eliminating the weed from
the management area. This strategy usually consumes
the greatest amount of time and resources and is applicable
mainly to newly-invading weeds that are confined to
a limited number of small areas.
Setting Treatment Action Levels
Sufficient resources are seldom available. Weed management
is a process that continues over many years, and weed
managers are continually prioritizing treatment areas
and balancing the priorities with their resources.
This process is called "setting treatment action
levels." When the weed population reaches an intolerable
level, a DOT takes action to treat it.
Two situations that increase the priority of a site
are 1) the discovery of a small "outlier" population,
a recent invasion from another area that must be taken
care of soon in order to prevent a bigger problem later,
or 2) the discovery that the weed population has become
a threat to agriculture, native plants, food sources
for wildlife, highway safety, water resources, etc.
Inevitably there are areas that are lower in priority
and will be tolerated for the short-term. Complete
eradication may not be practical unless the patches
are very small. Moreover, to maintain populations of
natural enemies, some individual plants must be permitted
to persist.
Setting treatment thresholds includes prioritizing
and balancing treatments with resources. Weeds will
be treated when populations increase beyond a predetermined
level. This level will largely depend on the characteristics
of the site and weed. In some cases the level may be
no weeds at all, and in other cases the number of weeds
you can tolerate may be much greater.
Establishing a Monitoring Program
In IVM, monitoring is the repeated inspection of
areas that may be subject to noxious weed problems.
Written records will allow comparison of inspections
over time to reveal how conditions are changing, especially
whether noxious weed populations are increasing or
decreasing.
- Focused limited monitoring resources on sites where
problems are most likely to occur. Public sightings
of new weed infestations may be encouraged through
an education or incentive program (see
Educating Vegetation Management Personnel and the
Public).
- Maintain records of your monitoring activities.
Creating standardized forms will make data collection
easier and help remind you to gather all the information
you need. Forms work best if they include labeled
blanks for all pertinent information and allow the
user to check or circle rather than having to write
words or numbers. See examples
of forms, which often include information such
as the name(s) of the person(s) collecting the data,
the location, and date of monitoring; a qualitative
description of the vegetation, such as the names of
the plants or types of plants (native vegetation,
annual/perennial weeds, trees, etc.) and stage of
growth (germinating, flowering, setting seed, etc.);
a quantitative description, such as percent cover,
density, size of the patch, or if possible, the number
of plants.
- Note special conditions such as unusual weather
events, and record treatment history, including information
on treatment applications (who, when, where, how,
cost, difficulties, and successes). This will allow
you to evaluate and fine-tune treatments.
Monitoring efforts should be scheduled to coincide
with critical life stages of the weed or its biological
controls. If possible, plan monitoring sessions alongside
other scheduled activities in the area to save time
and labor. After treatment activities and at the end
of the season, schedule monitoring sessions to help
you evaluate your program.
Evaluate the Vegetation Management Program
At the end of the season, evaluate and fine-tune
your program in order to improve it the next year.
Some questions to ask at the end of the season might
be: [N]
- Were the objectives of the management program met?
- Were all the necessary components of the program
actually developed?
- Were they integrated successfully? Were the right
people involved in the integration?
- Which control methods seem to be working and which
do not? Keep in mind, this is best answered
over a span of years.
- Do some of these methods need fine-tuning?
- What kind of follow-up is needed next year?
- How can I best communicate this information?
Costs are central to a decision to continue an IVM
program. It is important to keep in mind that the transition
period to IVM will probably involve investing in the
management of infested areas to achieve stable vegetation
that will reduce management costs in future years.
Native plants and other beneficial vegetation take
years to establish. Although you may find that total
annual costs drop during the first year of IVM, it
is also possible that costs may increase somewhat;
however, after two or three years costs should decline
and stabilize below the historical average.
Invasive Species Control Contacts at State DOTs
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