HomeMy WebLinkAbout921541.tiff AR2287OO2
ORDINANCE NO. 169
IN THE MATTER OF ADOPTING AND ENFORCING AN UNDESIRABLE PLANT MANAGEMENT PLAN FOR
THE COUNTY OF WELD, STATE OF COLORADO.
N C) BE IT ORDAINED BY THE BOARD OF COUNTY COMMISSIONERS OF WELD COUNTY, COLORADO:
o WHEREAS, the Board of County Commissioners of the County of Weld, State of
U Colorado, pursuant to Colorado statute and the Weld County Home Rule Charter, is
vested with the authority of administering the affairs of Weld County, Colorado,
o W and
0
o WHEREAS, Section 35-5.5-105(1) , CRS, requires the Board of County
w
• Commissioners of each County in the State of Colorado to adopt an Undesirable
p• Plant Management Plan for all of the unincorporated lands within the County to
take effect no later than January 1, 1992, and
a
WHEREAS, pursuant to Section 35-5.5-105 (1) , CRS, the Board may adopt and
provide for the enforcement of the Plan by Ordinance, and
o• P4
N a WHEREAS, this Ordinance will provide for the health, safety, welfare, of
m o all of the citizens of the County of Weld, State of Colorado, and
� z
W WHEREAS, pursuant to Sections 30-35-301 and 30-15-402, CRS, the Board of
m E County Commissioners has the authority to enact such Ordinances as said Board
o a deems necessary and proper to provide for the safety, preserve the health,
N promote prosperity, and improve the morals, order, comfort, and convenience of
o w the County and its inhabitants.
o r=
r
N z NOW, THEREFORE, BE IT ORDAINED by the Board of County Commissioners of the
N FC County of Weld, State of Colorado, that the following Undesirable Weed Management
0
• Plan is hereby adopted for all of the unincorporated lands within the County of
Weld, State of Colorado, to take effect upon the effective date of this Ordinance
gand that the enforcement provisions contained herein shall apply to all persons
in in who are required to control undesirable plants within the unincorporated areas
rn M of the County of Weld, State of Colorado, pursuant to the provisions of the Plan.
- o
Fq u, ARTICLE I - UNDESIRABLE PLANT MANAGEMENT PLAN
I. Introduction
A. Description of HB 90-1175, Undesirable Plant Management Act
The Undesirable Plant Management Act which was signed into law on
May 7, 1991 (CRS 35-5.5-101, et. seq. ) , states that certain
undesirable plants pose a threat to the continued economic and
environmental value of the land in Colorado and that they must be
managed by all landowners in the state. The undesirable plants
designated for mandatory management statewide are: leafy spurge
(Euphorbia esula) , Russian knapweed (Centaurea repens) , diffuse
knapweed (Centaurea diffusa) and spotted knapweed (Centaurea
maculosa) . Additional weed species may be added to the state list
by each local jurisdiction.
ORD169
921541
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 2
N
N
O
O The law states such that local governments (cities and counties) are
directed to take the necessary steps to manage the undesirable
plants in their respective jurisdictions. They are further directed
0 3 to appoint an advisory commission whose responsibilities are
o
• a threefold:
o W
O 1) develop recommended management criteria and integrated weed
Umanagement plans for managing the designated undesirable
plants;
a
2) recommend addition of undesirable plants that shall be subject
o x to integrated management;
N a 3) recommend to the County Commissioners those landowners who
C71 shall be required to submit integrated weed management plans
z for managing the undesirable plants on their property.
H
W
o y The law further states that by January 1, 1992, each local governing
body is to have developed and adopted an Undesirable Plant
N a Management Plan for all lands within its jurisdictional boundaries.
O a
0 14
m z II. Description of the County Weed Problem
N Z
No A. Weed Species in Weld County to be Controlled Pursuant to Weed
U a Control Laws
W �C
£ The Pest Control Districts Law (CRS 35-5-104) enabled landowners in
'^ `o each County the ability, through a lengthy petitioning and balloting
('1 N process, to establish weed control districts. Within each weed
'i district, designated species are mandated to be controlled. In Weld
M G+ County, 9 such weed districts exist. The districts occur in the
lower 2/3 of the county, and the weed species designated for control
range from 3-7 species depending upon the weed district. The weed
species that are currently being managed in at least a part of Weld
County are as follows:
Leafy spurge (Euphorbia esula) , Canada thistle (cirsium
arvense) , musk thistle (Carduus nutans) , field bindweed
(Convolvolus arvensis) , whitetop (Cardaria draba) , Russian
knapweed (Centaurea repens) and wild proso millet (Panicum
miliaceum) .
Under the Undesirable Plant Management Act (CRS 35-5.5-101, et seq)
there are four weed species which are mandated for county-wide
management. They are leafy spurge, and Russian, diffuse and
spotted knapweeds. Canada thistle and musk thistle have been added
to the County-wide undesirable plant list by the Weld County
Commissioners, in accordance with CRS 35-5.5-108(3) .
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 3
N0
NO
O
m o Of the weed species listed previously, Canada thistle, field
bindweed, leafy spurge, musk thistle, Russian knapweed, whitetop and
Q wild proso millet cover the most acreage in Weld County and pose the
o W greatest economic and environmental threat to the county. Diffuse
knapweed is currently localized to a few drainages and rights-of-way
o x in the southwest part of the County, and there are no known spotted
yr a knapweed infestations in the County.
0
III. Objectives and Goals
rl
: b A. Statement of Objectives
rn
WThe objectives of the Weld County Pest and Weed Department are
N a fourfold:
a O
1/4O Z 1. Develop and carry out a comprehensive noxious weed control
w program on all County right-of-way and other County property,
E such as in sand and gravel mining operations, grader shed lots
a and open space areas.
O W 2. Establish an educational program, by using mailings and
Or G` holding educational and calibration seminars, that will
m z effectively communicate weed management information to the
N 4 landowners in the County.
wa 3. Identify non-informed or negligent landowners who are not
uG S carrying out weed management programs on their property and
n N provide technical support for establishing weed management
m
r- plans or enforce on properties, if necessary.
O
W w 4. Work with all state and federal agencies, through
intergovernmental agreements, if necessary, towards
establishing effective weed management programs on their
property.
B. Short Term Goals (1-3 years)
1. Map all the County roads for noxious weed infestations.
2. Map on a computer program (Design CADD) at least half of the
landowners that have leafy spurge, Canada thistle and Russian
knapweed infestations.
3. Establish contact with every landowner on the South Platte and
Poudre Rivers that have leafy spurge.
4. Establish 3-5 educational/calibration seminars (annually) that
work directly with 150-200 landowners each year.
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 4
N
NO
5. Have established contact with the Colorado Department of
`" Highways, Dept. of Parks and Recreation, Colorado Land Board,
Division of Wildlife and U.S. Forest Service. Help them
develop Weed Management Plans and where appropriate enter into
wo cooperative intergovernmental agreements.
•
4#1-W 6. Have established 6-8 biological control release sites
throughout the County.
O
7. By the fourth year have reduced the noxious weed acreage
sprayed on County right-of-way by 15-20%.
.. w
rn
o a4 C. Long Term Goals (4-8 years)
N .W7 1. Have mapped on the computer program all the noxious weed
u infestations countywide, including private, state and federal
H lands.
W
o cq 2. Have reduced the noxious weed acreage sprayed on County right-
er of-way by 40-50%.
N
o w 3. Have contacted and worked with every landowner county-wide who
z has a noxious weed infestation.
N ,Z
N 4. Have established 30-50 biological control release sites in the
O a County.
W
IV. Plan of Work - Implementation
mco
M 111
m A. Description of Integrated Weed Management Techniques
M w The weed species designated as undesirable and mandated for
management are leafy spurge (Euphorbia esula) , Russian knapweed
(Centaurea repens) , diffuse knapweed (Centaurea diffusa) , spotted
knapweed (Centaurea maculosa) , Canada thistle (Cirsium arvense) and
musk thistle (Carduus nutans) . Integrated weed management methods
are to be used in managing these weed species (CRS 35-5.5-107) .
Integrated management techniques include education; preventive
measures; and control measures including cultural, mechanical,
biological and chemical control. For the purposes of this plan the
following definitions for the control measures will be used.
1. Cultural control means those methodologies or management
practices conducted to favor the growth of desirable plants
over undesirable plants, including but not limited to
maintaining an optimum fertility and plant moisture status in
an area, planting at optimum density and spatial arrangement
in an area, and planting species most suited to an area.
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
N O PAGE 5
NO
O
MO
U 2. Mechanical control means those methodologies or management
o practices that physically disrupt plant growth, including but
o w not limited to tilling, mowing, burning, flooding, mulching,
a 3 hand-pulling and hoeing.
orz
tnW
qx 3. Biological control means the use of organisms such as sheep,
O goats, cattle, insects and plant diseases to disrupt the
growth of undesirable plants.
.. w
4. Chemical control means the use of herbicides or plant growth
regulators to disrupt the growth of undesirable plants.
ox
N a Management of the various undesirable plants will vary depending
O upon the site the plant is located in. Management options for each
Z weed species will be developed for each site where the plant is
W found in Weld County.
to E
o w
rx The integrated management options listed below are meant to provide
N various management techniques for controlling the noxious weeds in
o w the various environmental sites they are found. By no means are all
no w the management options developed. Additional combinations of
o z management techniques are possible which may be submitted by private
landowners. The integrated weed management plans submitted by
✓ individual landowners will be evaluated by the Weld County
rj Vegetation Management Specialist and the Integrated Weed Management
a Advisory Commission on a case by case basis.
u rn
M N B. Integrated Weed Management Options for Each Weed Species
r10
XI 44 Leafy Spurge: Leafy spurge is a deep rooted perennial plant that
spreads by seeds and creeping roots. It has a vast underground root
system which makes it difficult to control with any one control
technique. Leafy spurge is found primarily in riparian sites (along
waterways such as the Poudre and South Platte Rivers) in Weld County
and also along irrigation ditches, range and pastures, roadsides and
other non cropland sites.
1. Control Measures
a. Cultural Control: Seeding perennial grasses and forbs
can be an effective management tool. Early emerging
plant species that utilize early season moisture such as
smooth brome (Bromus inermis) or crested wheatgrass
(Agropyron cristatum) have reduced leafy spurge density
and limited the spread and establishment of new
infestation. Sequential glyphosate applications
followed by a seeding of Luna Pubescent Wheatgrass,
Ephraim Crested Wheatgrass, Intermediate Wheatgrass,
Sherman Big Bluegrass or Bozoisky Russian Wild Rye has
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
N p PAGE 6
N U
O
0
U shown to be very effective in reducing an existing stand
Aof leafy spurge.
o W
og
b. Mechanical Control: Mechanical control of leafy spurge
Wis difficult at best, however, repeated mowing every 14-
21 days throughout the summer, starting before flowering
a
0 stage, will at least keep the plants from going to seed
and may reduce the underground root reserve. Research
a results are not available to indicate whether stand
reduction or eradication could be achieved through use
O1 of this technique.
N ] c. Biological Control: Grazing with sheep and goats
°\ U throughout the spring, summer, and fall will keep leafy
2 spurge from going to seed and may reduce the underground
w root reserve. This practice may also weaken the plants
`^ Er
Ocn to make them more susceptible to chemical control.
N D Several insect species that have been released by the
o
o USDA in the United States are showing some control of
w
leafy spurge. Two species of flea beatles, Apthona
N z flava and Apthona nigriscutis feed on leafy spurge.
No Adults feed on the foliage during the summer and the
o larvae burrow through the soil and mine the roots and
Wx fine root hairs. These insects used alone may not
control leafy spurge. When used along with other
o insects such as Spurgia esula, a gall midge which feeds
N N on the flowers preventing seed production, they will
" o weaken the plant and make it more susceptible to other
Ce w control methods, particularly chemical control.
d. Chemical Control: There are a number of herbicides
labelled for use on leafy spurge. Those that can be
used independently or in combination with each other
are: picloram (Tordon) , dicamba (Banvel) , 2-4-D (many
different formulations) , glyphosate (Roundup and Rodeo)
and fosamine (Krenite) .
2. Integrated Management Options by site
a. Range, Pasture and Riparian Sites
Option #1 Biological and Chemical Control: Grazing with
sheep or goats from early April through late August -
early September followed by a herbicide treatment in
late September - early October.
Option #2 Biological and Chemical Control: The release
of insects such as Apthona nigriscutis, Apthona flava
and/or Spurgia esula can be made. A herbicide treatment
0RD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
N PAGE 7
N U
O
N▪ O
U can then be made during the true flower stage (where
Ca insects were not released) and in the fall where insects
o W were released. Herbicide applications should only be
0 3 carried out in the fall, where insects are used. Use of
a herbicides at different times of the growing season can
te-
a be instituted as additional IPM research is conducted
O and recommendations are developed.
U
zOption #3 Mechanical and Chemical Control: Mowing can
Ln
; be carried out throughout the season with the first
mowing cycle at the bud stage. Mowing should stop
o during late August followed by a herbicide treatment
N during late September-early October, before a hard
rn U freeze.
10 2
H
Option #4 Biological or Mechanical Control Only: The
LC) E use of sheep or goats or mowing should be used all
o a season to keep leafy spurge from going to seed. Whether
this method will keep the existing infestation from
o• W spreading by underground root growth is uncertain.
o W
N Z Option #5 Chemical Control Only: Herbicides should be
c1/41 LLc used in the spring, early summer during the true flower
stage and in the fall just before a hard freeze. Only
U a the herbicides labelled for the site intended will be
W
used.
L.n
M `.0 b. Along Irrigation Ditches
o
• e, Option #1 Biological and Chemical Control: The release
of insects such as Apthona nigriscutis, Apthona flava
and/or Spurgia esula could be made. A herbicide
treatment should be carried out at the true flower stage
(if the Spurgia esula has not kept the plants from going
to seed) and/or in the fall just before a hard freeze.
Option #2 Chemical Control Only: Herbicides can be used
in the spring-early summer during the true flower stage
and in the fall just before a hard freeze. Only the
herbicides labelled for the site intended will be used.
c. Road Right-of-Ways and Other Non-Crop Areas
Option #1 Mechanical and Chemical Control: One mowing
cycle can be carried out at the bud to early flower
stage. A herbicide application should be made at the
true flower stage.
Option #2 Chemical Control Only: Herbicides can be used
in the spring-early summer during the true flower stage
0RD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 8
NO
NU
O
CO 0 and in the fall just before a hard freeze. Only the
V herbicides labelled for use on roadsides and other non-
cropland areas would be used.
0w
O Russian Knapweed: Russian knapweed is a non-native perennial plant
ca w that spreads by seeds and creeping roots. It has the ability to
release chemicals into the environment as foliage decays which
pinhibit the growth of surrounding vegetation (allelopathic
properties) . Thus, once established Russian knapweed can colonize
aan area rapidly. Russian knapweed is found primarily in range and
pastures, roadsides and other non-cropland sites in Weld County.
o a 1. Control Measures
w
N a
U a. Cultural Control: Seeding perennial grasses such as
z smooth brome (Bromus inermis) will help to compete with
Fl Russian knapweed and slow its spread. In addition,
N N stimulating grass growth by fertilizing and/or
oEn
irrigation should increase grass competition. Due to
the allelopathic properties of Russian knapweed, other
o w control techniques such as judicious chemical control
o
would have to be implemented in order to give grasses a
00 z
N chance to compete.
N 4
O
b. Mechanical Control: Mechanical control of Russian
(JIM
knapweed could be carried out throughout the summer with
a £ repeated mowing every 14-21 days. This would at least
u N keep Russian knapweed from going to seed. Whether this
m control technique will reduce the root mass and
O subsequently reduce an existing stand is not known.
W
c. Biological Control: There are currently no biological
control agents available for Russian knapweed.
d. Chemical Control: There are a number of herbicides
labelled for use on Russian knapweed. Those that can be
used independently or in combination with each other
are: chlorsulfuron (Telar) , picloram (Tordon) , 2-4-D
(many different formulations) and glyphosate (Roundup
and Rodeo) .
2. Integrated Management Options by site.
a. Range and Pastures
Option #1 Mechanical and Chemical Control: Mowing can
be carried out throughout the season with the first and
successive mowing cycles carried out at the bud stage.
A herbicide treatment can then be made in the fall
before a hard freeze.
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 9
NN O Option #2 Cultural and Chemical Control: A herbicide
application, using short residual herbicides such as
O U glyphosate and/or 2-4-D, can be made followed up by
reseeding with a competitive grass such as smooth brome
o
,a or other sod forming species. In addition,
mica fertilization or irrigation could be instituted to
• stimulate increase grass growth.
rz
yr W
a Option #3 Chemical Control Only: Herbicide applications
O can be made to Russian knapweed during the bud stage,
Wbloom to post-bloom and/or in the fall, depending upon
"'i a herbicide used.
in
.. w
o x b. Road right of way and other non-crop areas.
W
N U Option #1 Mechanical and Chemical Control: One mowing
Cr) cycle can be carried out at the bud to early flower
1O 2 stage. A herbicide application can be made during the
o\ w bud stage, bloom to post-bloom and/or in the fall,
o y depending upon the herbicide used.
IX
N p Option #2 Cultural and Chemical Control: Use of short
o w residual herbicides such as glyphosate and/or 2-4-D can
'- be used in the early summer during the bud stage.
N Z Seeding with perennial grasses such as smooth brome,
No Luna Pubescent Wheatgrass, Ephraim Crested Wheatgrass,
U a Intermediate Wheatgrass, Sherman Big Bluegrass or
w Bozoisky Russian Wild Rye can than be carried out later
a in the summer, at the appropriate time.
en• W
N N Option #3 Chemical Only: Herbicide applications can be
- o made during the bud stage, bloom to post bloom and/or in
W w the fall, depending upon the herbicide used.
Diffuse Knapweed: Diffuse knapweed is a non-native, biennial to
short lived perennial forb that reproduces by seed. It spreads
rapidly by the mature plant breaking off at ground level and being
blown with the wind, dispersing seed. It is a pioneer species that
will quickly invade disturbed, dry sites. Diffuse knapweed is found
in the southwest part of Weld County along rights-of-way, dry
pasture sites and in gravelly riparian sites, such as along Boulder
Creek and the St. Vrain and South Platte Rivers.
1. Control Measures
a. Cultural Control: Cultural Control of diffuse knapweed
is similar to Russian knapweed in that seeding with
perennial grasses such as smooth brome and crested
wheatgrass will help to compete with diffuse knapweed
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
N VO PAGE 10
o O
0 and slow its spread. Seeding alone in infested sites
o w will not, however, control the existing stand.
3
o ix b. Mechanical Control: Mowing diffuse knapweed when it is
in the bud stage and again when it is flowering can
significantly reduce seed production. Keeping diffuse
knapweed from going to seed over a number of years can
eventually eliminate an infestation, once the seed
0 source in the soil is depleted.
•• w
rn
o x c. Biological Control: Two species of picture-winged
Wflies, Urophora affinis and U. quadrifasciata have
CV
U demonstrated the ability to reduce the seed production
of diffuse and spotted knapweed. The flies lay eggs on
o H the developing seed heads. As a result of the larvae
Hfeeding on the flowering heads, the plants produce galls
o Cf) which reduces seed production. The Colorado insectary
Wis currently rearing these two flies and has made
CV o w releases in the state the last 3 years.
o
m Z d. Chemical Control: There are a few herbicides labelled
N 4 for use on diffuse knapweed. Those that can be used
o independently or in combination with each other are:
o a picloram (Tordon) , dicamba (Banvel), glyphosate
w Roundu
( p) , and 2-4-D (many different formulations) .
M to 2. Integrated Management Options by site
en
o
w a. Pasture and riparian areas
Option 41 Cultural and Chemical Control: A herbicide
application can be made in early summer when diffuse
knapweed is in the rosette through bolting stage.
Reseeding with competitive perennial grasses such as
smooth brome and crested wheatgrass can be followed
later in the summer depending upon the herbicide used
and rate of application.
Option #2 Biological and Chemical Control: The release
of insects such as Urophora affinis and U.
quadrifasciata can be made. A herbicide treatment can
than be made from the rosette through bolting stage
(where insects were not released) and in the fall where
insects were released. Herbicide applications should
only be carried out in the fall, where insects are used.
Use of herbicides at different times of the growing
season can be instituted as additional IPM research is
conducted and recommendations are developed.
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 11
N 0 Option #3 Mechanical and Chemical Control: Mowing can
o be carried out when diffuse knapweed is in the bud stage
and again at flowering. A herbicide application can
ri 0U then be made to any plants that have rebolted, if
q necessary.
a
o
0 3 Option #4 Mechanical Control Only: Mowing can be
o g carried out throughout the season, reducing seed set.
«� W
Option #5 Chemical Control Only: Herbicide application
can be made during the rosette stage, spring or fall,
and while bolting.
" b. Right-of-Ways and other non-crop areas
ox
Option #1 Cultural and Chemical Control: Same as for
U Option #1 in Pasture and Riparian Areas.
H Option #2 Mechanical and Chemical Control: One mowing
operation can be carried out when diffuse knapweed is in
o a the bud stage. If necessary, a herbicide application
can be made to plants that have rebolted.
C4 Ca
o W
o G*+ Option #3 Mechanical Control Only: Same as for option
m z #4 in Pasture and Riparian Areas.
N z
N R4
o Option #4 Chemical Control Only: Same as for Option #5
o a in Pasture and Riparian Areas.
Spotted Knapweed: Spotted knapweed is a non-native, perennial forb
tfl
rn that reproduces by seed. It is a highly competitive plant in
c rangeland sites that will exclude most grasses and forbs with time.
There are currently no known spotted knapweed infestations in Weld
County.
1. Control Measures
a. Cultural Control: Cultural Control of spotted knapweed
is similar to Russian and diffuse knapweed in that
seeding with perennial grasses such as smooth brome and
crested wheatgrass will help to compete with spotted
knapweed and slow its spread. Seeding infested sites
will not, however, control the existing stand. In range
and pasture conditions, good grazing management
practices will help to reduce the spread of the
knapweeds in general.
b. Mechanical Control: Mechanical control of spotted
knapweed could be carried out throughout the summer with
repeated mowing every 14-21 days. This would at least
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 12
N O
N U
keep spotted knapweed from going to seed. Whether this
r•4
U control technique will reduce the root mass and
subsequently reduce an existing stand is not known.
0
a
0 3 c. Biological Control: The same as what was developed
o
• under biological control for diffuse knapweed.
o W
en w
d. Chemical Control: There are a few herbicides labelled
O for use on spotted knapweed. Those that can be used
independently or in combination with each other are:
"; p+ picloram (Tordon) , dicamba (Banvel) , 2-4-D (many
different formulations and clopyrald and 2-4-D
° Z (Curtail) .
N .w7 Canada Thistle: Canada thistle is an aggressive, creeping perennial
°� that reproduces by seed and vegetative buds in the root system. It
`° W is a difficult plant to control because of its extensive root
w system. Vertical roots may grow 6-15 foot deep and horizontal roots
No C./) may extend 15 feet or more. Canada thistle is the most widespread
noxious weed in Weld County. It can be found in most habitat types
N a including: pastures, riparian sites (along waterways such as the
0 Poudre, South Platte, St. Vrain and Big Thompson Rivers) , irrigation
m ditches, along roadside rights-of-way and in the various crop and
N Z non-cropland sites.
ni
a1. Control Measures
a. Cultural Control: Plant competition from various
`° grasses and from alfalfa can be an effective management
M N tool. Early emerging grass species such as smooth brome
- O and crested wheatgrass can be used to compete with
m w Canada thistle and slow the spread and establishment of
new infestations. Competition alone, however, is seldom
effective on Canada thistle.
b. Mechanical Control: Mechanical Control of Canada
thistle could be carried out throughout the summer with
repeated mowing every 14 days. This would keep Canada
thistle from going to seed; however, mowing has shown to
stimulate new shoot growth from roots. Consequently,
mowing alone may increase shoot density in an
established stand. Whether consistent mowing for
consecutive years (2-3 years) will reduce the root mass
and subsequently reduce an existing stand is unknown.
c. Biological Control: There is one insect species, a
weevil, called Ceutorynchus litura, that is currently
being used as a biological control agent on Canada
thistle in Colorado. The female lays eggs on the
underside of the leaves in early spring and then the
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 13
NO
N
larvae bore into the main leaf vein and migrate down to
en 0
the crown of the plant. The holes created by the larvae
open up Canada thistle to secondary infection. Where
high numbers of the larvae occur death of Canada thistle
oW
o � can occur.
o W EA- d. Chemical Control: There are a number of herbicides
Ca labelled for use on Canada thistle, depending upon where
U the thistle is found. The herbicides that can be used
independently or in combination with other compounds
Ln are: picloram (Tordon) , dicamba (Banvel) , 2-4-D (many
- different formulations) , chlorsulfuron (Telar) ,
o x clopyralid (Curtail, Stinger, Transline) and glyphosate
(Roundup, Rodeo) .
N
U 2. Integrated Management Options by Site
�• Z
H
W a. Range, Pasture and Riparian Sites
in H
oul
Option #1 Biological and Chemical Control: Release of
o the insect Ceutorynchus litura can be made during the
o w early summer. A herbicide application can then be made
at the bud stage (where insects were not released) and
co z
in the fall where insects were released. Herbicide
o applications should only be carried out in the fall,
U a where insects were directly released. Use of herbicides
wx at different times of the growing season can be
instituted as additional IPM research is coordinated and
`n r- recommendations are developed.
el VD
M l
Option #2 Mechanical and Chemical Control: Mowing can
w be carried out throughout the season with the first
mowing cycle at the bud stage. Mowing should stop
during late August followed by a herbicide treatment
during late September through October, before a hard
freeze.
Option #3 Cultural and Chemical Control: A herbicide
application, using short residual herbicides such as
glyphosate and/or 2-4-D, can be made followed up by
reseeding with a competitive grass such as smooth brome
or other sod forming species. In addition,
fertilization or irrigation could be instituted to
stimulate increase grass growth.
Option #4 Chemical Control Only: Herbicide applications
can be made to Canada thistle from rosette to the bud
stage, and/or in the fall, depending upon the herbicide
used.
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 14
N O
N
o b. Road Right-of-Ways and other Non-Crop Areas
c
Option #1 Mechanical and Chemical Control: One mowing
cycle can be carried out at the bud to early flower
o w stage. A herbicide application can be made from rosette
to bud stage and/or in the fall, depending upon the
•
o• W herbicide used.
O
O Option #2 Cultural and Chemical Control: A herbicide
application can be made in early summer when Canada
.-i a thistle is in the rosette through bud stage. Reseeding
`^ with competitive perennial grasses such as smooth brome
.. w
rn and crested wheatgrass can be followed later in the
o a summer depending upon the herbicide used and rate of
N a application.
m U
• z Option #3 Chemical Control Only: Herbicide applications
o 'i can be made from rosette to bud stage, and/or in the
Le-) E fall, depending upon the herbicide used.
o m
a
N c. Cropland Sites
ow
0 44
Canada thistle is found in almost every crop grown in
N Z Weld County. Prescription weed management measures
N < developed by the CSU weed scientists and the Weld County
o Extension Agronomist will be used.
Ug
a Musk Thistle: Musk thistle is a biennial plant that reproduces only
In m by seed. Rosettes (clump of leaves on the ground) are formed during
^' ° the first year of growth and the plant bolts and sets seed the
Mr-
.-1 o second year. It is a prolific seed producer with a single plant
M producing up to 20, 000 seeds. Musk thistle is found primarily in
pastures and riparian sites (along waterways such as the South
Platte, St. Vrain, Big Thompson, and Little Thompson drainages and
Boulder Creek) and along irrigation ditches, roadside rights-of-way
and other non-crop areas.
1. Control Measures
a. Cultural Control: Maintaining pastures and riparian
sites in good condition is the primary method of
culturally managing musk thistle. Promoting good grass
growth by proper grazing management and fertilizing
according to soil testing recommendations will prevent
establishment of musk thistle.
b. Mechanical Control: Musk thistle can be effectively
controlled mechanically. Severing the roots below
ground with a shovel or hoe or mowing musk thistle every
time it reaches early flower stage will reduce, if not
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 15
N O
N O
Lf) eliminate, seed production. If mowing occurs mid to
'" U late flower stage the thistle should be gathered and
burned to destroy any seed that has developed.
a
ow
0 c. Biological Control: Two species of weevils, Rhinocyllus
o z conicus (seed head weevil) and Trichosirocalus horridus,
"' w attack two different sites of musk thistle. The seed
O head weevil, as its name implies, attacks the seeds of
musk thistle. Eggs are laid by the female on the back
.-4 of developing flowers and then the larvae bore into the
flower, destroying the developing seed. The seed head
weevil can reduce seed production by as much as 50%.
o
Use of this weevil as the sole means of controlling musk
thistle is not very effective.
N
m
1/4.Oz
Trichosirocalus horridus attacks the crown area of musk
CZ) H thistle rosettes, killing or weakening the plant before
n E it bolts. Use of both weevil species together may prove
ato be an effective biological control program.
o W d. Chemical Control: There are a number of herbicides
o
labelled for use on Musk thistle, depending upon where
ro z the thistle is found. The herbicides that can be used
N independently or in combination with other compounds
o are: picloram (Tordon) , dicamba (Banvel) , 2-4-D (many
O W different formulations) , chlorsulfuron (Telar) ,
rx clopyralid (Curtail, Stinger, Transline) and glyphosate
,n in (Roundup, Rodeo) .
M co
M
0 2. Integrated Management Options by Site
W
a. Pasture and Riparian Sites
Option #1 Biological and Chemical Control: Release of
Trichosirocalus horridus can be made at the appropriate
time of the summer. Rhinocyllus conicus is well
established in Weld County and should already be
infesting the stand. A herbicide application can then
be made to musk thistle at the flower stage. Telar or
Escort should be used when treating musk thistle in the
flower stage. Herbicide applications should only be
carried out in the flower stage in order to allow the
seed head weevil to complete its life cycle. Use of
herbicides to rosettes in the spring or fall should not
be carried out where Trichosirocalus horridus was
released. Use of herbicides at different times of the
growing season can be instituted as additional IPM
research is conducted and recommendations are developed.
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 16
Option #2 Mechanical and Chemical Control: Mowing can
be carried out throughout the summer when musk thistle
N O
N U is in the bud to early flower stage. A herbicide
o\ application can than be made in October to the fall
a rosettes and any bolted plants.
v
Ca Option #3 Mechanical Control Only: Mowing can be
oo 3 carried out throughout the summer when musk thistle is
o
in the bud to early flower stage, keeping it from
o a producing seed. If mowing occurs mid to late flower
a4 a stage the thistle should be gathered and burned to
O destroy any seed that has developed.
V
,-.4c4 Option #4 Chemical Control Only: Herbicides can be used
`: ,n in the spring and fall when the plant is in the rosette
O1 stage. Only the herbicides labelled for the site
o a intended will be used.
w
N a
o` U b. Road Right-of-Ways and other Non Crop Areas
‘.0z
CD W Option #1 Biological and Chemical Control: Same as for
rn E option #1 in Pasture and Riparian sites.
ocn
a
N O Option #2 Mechanical and Chemical Control: One mowing
o w pass can be made when musk thistle is in the bud to
r early flower stage. A herbicide application can be made
re Z
N z in the fall to the rosettes and rebolted plants.
N r4
0
Option #3 Chemical Control Only: Herbicides can be used
Wa g in the spring and the fall when the plant is in the
rosette stage. Only the herbicides labelled for the
rn 0 site intended will be used.
M (--
en r-
--' O C. Prevention Measures
Preventive control means using measures which will stop or forestall
weeds from contaminating an area. Establishing preventive measures
are often the most practical and cost effective means of weed
control.
The preventive measures which seem most practical for Weld County
are as follows, 1) establishing weed free seed and mulch
requirements for reclamation of disturbed sites, 2) promoting the
Colorado Weed Free Hay and Forage program, 3) prioritizing weed
management areas along routes of dispersal, and 4) identifying
noxious weed species in counties bordering Weld County.
0RD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 17
1. Weed Free Seed and Mulch Standards
N O
N U Where the ground is disturbed by activities, such as road
preparation for road resurfacing, sand and gravel lot
operations and oil and gas well operations, weeds will be the
C] first plants to colonize or revegetate the site. It is
important that these sites be reclaimed so that noxious weeds
00 w do not become established.
o W Weld County will establish standards for using weed free seed
and mulch on all county operations concerned with the
0 reclamation of disturbed sites, such as on roadside
resurfacing projects and sand and gravel lot operations.
'"4o Additional regulations may be considered for similar
Lin
•• ++ operations being carried out on private land.
oW
2. Weed Free Hay and Forage Program
Na
°� U Standards are currently being developed that will enable
Hgrowers the ability to have their hay and forage certified as
� w noxious weed free. These standards will encourage growers to
o CO produce noxious weed free hay and forage so that it can be
shipped and used anywhere in the U.S. (particularly where
N D noxious weed free standards currently exist) .
ID 14
ow
r z The Weld County Vegetation Management Specialist will provide
z an inspection and certification service and will promote the
N
Colorado Weed Free Forage Standards, through the use of
U a seminars, radio spots and newspaper articles.
w
3. Prioritizing Weed Management Areas Along Routes of Dispersal
r
en ri r Weeds are spread rapidly through the dispersal of weed seeds
o in air and water. Consequently, high weed seed dispersal
ccl G. areas are associated with right-of-ways, such as along all
roads and railroads and along waterways, i.e. , along the
Poudre, South Platte, St. Vrain and Little Thompson Rivers and
irrigation canals.
The County Pest and Weed Department will carry out a noxious
weed control program on all county roads from May through
September. The noxious weeds targeted for control include;
Canada, musk and bull thistle; leafy spurge; Russian, diffuse
and spotted knapweed; field bindweed; whitetop; and wild proso
millet. In addition, contact will be made with the Colorado
Department of Highways, all irrigation and ditch companies in
the County and the Union Pacific, Burlington Northern and
Great Western Railroad companies. Information regarding the
Undesirable Plant Management Act will be distributed and their
cooperation will be encouraged. Assistance in helping them
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 18
N Q
No U develop their integrated weed management programs will be
offered.
co 0
HI U
O In working with landowners on private property, all lands
w
bordering the rivers in the county will be considered high
o
0 3 priority areas. Landowner compliance with the Undesirable
o a Plant Management Act will be encouraged.
6414
CI 4. Identifying Noxious Weeds in Bordering Counties That Do Not
Q Occur in Weld County
U
W
L a Contact will be made with the weed control departments in the
''° bordering counties to identify the noxious weed species which
rn
o x occur in each county that would threaten Weld County. Plans
W will be developed to monitor the borders of Weld County, as
N U necessary.
W H D. Educational Programs
--, W
Ill
VI Education of the public is one of the most important components of
g a Weed Management program. Emphasis will be placed on continuing a
No w multifaceted educational program. The following programs have been
o [_, instituted in the past and will continue to be conducted every year.
r
coz
N Z 1. Timely newspaper articles concerned with weed identification
o and management.
U a
W2. Timely radio broadcasts following the information in the
newspaper articles.
Ul N
M c-
m r 3. Conducting landowner weed management seminars and calibration
� o
workshops.
m 44
4. Having an educational booth at the Colorado Farm Show.
5. Utilizing brochures and SIA's to hand out to individual
landowners.
E. Mapping
Establishing an accurate baseline map of the existing noxious weed
infestations in the county is extremely important for the ongoing
evaluation of the effectiveness of the county weed management
program. Therefore, a computerized mapping program will be
established that will map the noxious weeds established in Weld
County.
County roadsides will be mapped using a computer and
printer/datalogger on the spray equipment. Private and state land
will be mapped by Pest and Weed Department personnel taking aerial
0RD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 19
maps from the County Assessor's Office into the field and mapping on
site. Through the use of the Design CADD computer mapping program
N O and a digitizer, the noxious weed infestations will be mapped. All
No U mapping information will be stored in the county IBM computer
systems and can be retrieved for future evaluation.
al O
4U
F. Establishing Cooperative Intergovernmental Agreements
a
0 3 Contact will be made with the following agencies concerning
o a compliance with the Colorado Undesirable Plant Management Act.
o
a1. Colorado State Department of Highways
0
U
2. Colorado State Department of Parks and Recreation
" A 3. Colorado Division of Wildlife
o
4. Colorado State Land Board
N
rnU
5. U.S. Forest Service
oH
w Assistance will be offered in helping each agency develop integrated
o a weed management plans for their lands. Actual assistance in
carrying out the weed control programs on their properties will also
be offered. Cooperative intergovernmental agreements can be
o w established if Weld County is asked to assist in implementing the
w z weed control measures.
Nz
C•4 G. Adopt a Roadside Program
a
wa An Adopt a Roadside Program will be established which will give
landowners the ability to take the responsibility to manage the
m noxious weeds on the county rights-of-way that borders their
r property.
oa Landowners who are chemically sensitive or for some reason do not
want chemicals sprayed or mowing activities carried out along their
property, can take the responsibility for managing the noxious weeds
on the roadside right-of-way. Landowner agreements with specific
requirements for compliance will be established.
H. Enforcement on Private and Public Property
Cooperation from all landowners (private and state) will be
encouraged through positive communication by mail and through
personal contact. When weed control measures are not carried out by
a landowner, enforcement measures may have to be instituted. All
procedures as established by the Undesirable Plant Management Law,
CRS 35-5.5-109, the Pest Control Districts Law, CRS 35-5-108, and
any and all federal, state, and local regulations will be followed,
0RD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 20
for enforcement on private or public property. Integrated weed
N O management plans will be requested from certain landowners, as
N U determined by the county vegetation management specialist and the
Undesirable Plant Management Advisory Board. Work priorities must
N OU be established due to the size of the county and the number of
landowners with existing noxious weed problems. The following list
prioritizes where enforcement activities will be carried out in
0 3 ranking order of importance.
o W 1. Lands bordering all waterways (rivers and irrigation ditches) .
L1
O 2. Complaint properties.
3. Landowners identified as negligent in the past.
.. w
o x 4. Landowners with 5 or more acres of noxious weeds.
N V. Evaluation of Program
rnU
Z The goals and the plan of work established in chapters 3 and 4 of this
W document will be reviewed and evaluated at the end of every year. A
o m written evaluation will be prepared establishing additions or changes in
the plan of work for the following year. Any additions or changes shall
N 5 be approved by the Undesirable Plant Management Advisory Board and the
0 W Board of County Commissioners.
r
N Z The Weld County Undesirable Plant Management Plan shall be reviewed and
amended, as needed, at least every three years (CRS 35-5.5-107(4) (a)) .
>4
VI. No Waiver of Immunities/No Creation of Duties, Standard of Care, or Rights
for Third Parties
M1--
m No portion of this Undesirable Plant Management Plan shall be deemed to
~ constitute a waiver of any immunities which Weld County, Colorado, by and
Z G+ through the Board of County Commissioners of Weld County, or any pest
control districts and/or their Boards, or the Weld County Undesirable
Plant Management Advisory Commission or their officers or employees may
possess, nor shall any provision of this Plan be construed to create any
duty, standard of care or rights in favor of any third parties with the
respect to any obligation created by this Plan.
ARTICLE II - ENFORCEMENT OF UNDESIRABLE PLANT MANAGEMENT PLAN
Section 1 - Authorized Agent for Enforcement: Pursuant to Section
35-5.5-105(2) , CRS, the Weld County Vegetation Management
Specialist, his employees and agents, are hereby authorized to
enforce the above stated Undesirable Plant Management Plan in the
unincorporated areas of County of Weld, State of Colorado, by
utilizing those procedures set forth in Section 35-5-108, CRS,
Section 35-5.5-109, CRS, and any and all applicable State and
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 21
N o Federal Statutes, rules, regulations, and ordinances, including the
N U remaining provisions of this Ordinance No. 169.
▪ •
N OU Section 2 - Right of Entry: Prior to entering private lands for the
purpose of enforcing the Weld County Undesirable Plant Management
Plan, the Weld County Vegetation Management Specialist shall first
00 obtain a "right of entry" from the Board of County Commissioners, no
c a less than ten days after a Notice to Control Identified Undesirable
69 W Plants has been sent to the owner or occupant of the private lands
and said owner or occupant has failed to comply with said notice.
O
Section 3 - Mailing of Assessments: All assessments for the whole
^' a cost of any enforcement work performed by the Weld County Vegetation
Ln
- w Management Specialist or his designee(s) upon private lands,
x including up to 15% for inspection and other incidental costs in
e4 connection therewith, shall be mailed to the landowner or occupant
N ,.a by certified mail. Failure to receive said assessment shall not act
C" as a defense to said assessment.
� H
O H
Section 4 - Failure to Pay Assessment: Any assessment which is not
o u) paid within thirty-three days after the date of mailing by certified
tx mail to the landowner or occupant of private lands upon which the
N a Weld County Vegetation Management Specialist or his designee(s) have
o w performed enforcement work, shall constitute a lien against each lot
or tract of land until paid and may be certified by resolution of
NZ the Board of County Commissioners to the Weld County Treasurer's
Office to be collected in the same manner as provided for collection
o a of taxes upon the private lands in accordance with Section 35-5.5-
Wx g 109 (5) (a) , CRS.
LEI LEI ARTICLE III - SEVERABILITY
m l
m r--
r-1 O Section 1. If any section, subsection, paragraph, sentence, clause
• 44 or phrase of this Ordinance No. 169 is, for any reason, held or
decided to be invalid or unconstitutional, such decision shall not
effect the validity of the remaining portions.
Section 2. The Board of County Commissioners Weld County, Colorado,
hereby declares that it would have passed this Ordinance No. 169,
and in each and every section, subsection, paragraph, sentence,
clause and phrase thereof irrespective of the fact that any one or
more sections, subsections, paragraphs, sentences, clauses, or
phrases might be declared to be unconstitutional or invalid.
ARTICLE IV - LIABILITY
This Ordinance No. 169 shall not be intended to create a civil cause of
action against the Board of County Commissioners Weld County, Colorado, or any
other person that may administer this Ordinance No. 169 in any manner.
ORD169
ORDINANCE 169 - UNDESIRABLE PLANT MANAGEMENT
PAGE 22
O ARTICLE V - EFFECTIVE DATE
N
BE IT FURTHER ORDAINED by the Board of County Commissioners of Weld County,
n: O Colorado, that this Ordinance No. 169 shall become effective five days after its
N U
final public notice, in accordance with Section 3-14 (2) of the Weld County Home
Rule Charter.
ow
o The above and foregoing Ordinance No. 169 was, on motion duly made and
o g
seconded, adopted by the following vote on the 4th day of May, A.D. , 1992.
BOARD OF COUNTY COMMISSIONERS
ATTEST: (/ g' ain WELD COUNTY, COLORADO
iiir/1P
.-a aLn
,
Weld County Clerk to gle Board
l_ll a Ge rge Kenny, Chairman
0
N BY: EXCUSED
O1 U De Clerk to the Boar Constance L. Harbert, Pro-Tem
V0 2
H
APPROVED ASy 'FORM: vt
o cEn C. W. Kir
N0
o w County Attorney Gor . Lac
o W
o
N• 4 W. . Webster
Ua
w
x
U FIRST READING: March 11, 1992
el fl C- PUBLICATION: March 12, 1992
HI o
CO k+ SECOND READING: March 23, 1992
PUBLICATION: March 26, 1992
FIRST READING, REVISED: April 6, 1992
PUBLICATION: April 9, 1992
SECOND READING, REVISED: April 20, 1992
PUBLICATION: April 23, 1992
FINAL READING, REVISED: May 4, 1992
PUBLICATION: May 7, 1992
EFFECTIVE DATE: May 12, 1992
ORD169
•
•
STATE OF COLORADO )
•
COUNTY OF WELD )c.c. •
)
David S. Reynolds, being duly sworn,
says that he is publisher of ;
The New News, a weekly newsy. ATar Niewa Pa@p 1Z published in K burp in c: =
and state; that said newspae ORDINANCE NO. 169
general circulation in saidp
and has been canton any •'IN THE MATTER OF ADOPTING AND ENFORCING AN UNDESIRABLE PLANT MANAGEMENT PLAN FOR
uninterruptedly • publ;sherd the THE COUNTY OF WELD, STATE OF COLORADO.
during a •period 01 at least
f f f ty"twO consecutive weeks
the first publication 01 the THE IT ORDAINED BY T BOARD or COUNTY COMMISSIONERS OF WELD COUNTY, COLORADO:
notice; that said newspaper i WHEREAS, the Board of County Commissioners of the County of Weld, State of
newspaper wi •thin Colorado, pursuant to Colorado statute and the Weld County Home Rule Charter, is
act of the meaning vested with the authority of administering the affairs of Weld County, Colorado,
the 6 1 Assembly o and
state of Colorado,• entitled r,
to regulate the printing of l.' WHEREAS, Section 35-5.5-105(1), CRS, requires the Board of County
otices and , j Cissieners of each County in the State of Colorado to adopt as Undesirable
advertisements 'e Plant Management Plan for all of the unincorporated lands within the County to
amendments thereto; g
that the � take effect no later than January 1, 1992, and
of which thy annexed is a prig WHEREAS, pursuant to section 35-5.5-105 (1), CRS. the Board may adopt end
copy taken from said news a provide for the enforcement of the Plan by Ordinance, and
published in said newspaper,l@,
the re WHEREAS, this Ordinance will provide for Lhi health, safety, welfare. of
regular and entire issue
every number thereof , c all of the citizen; of the county of Weld, State of Colorado, and
WHEREAS, pursuant to Sections 30-35-301 and 30-15-402, CRS, the Board of
'4ZVt - y 0t1-er y
G+nCe D County Commissioners has the authorit to enact such Ordinances as said Board
i week for ) deems necessary and proper to provide for the safety, preserve the health,
Yee semi W4 weeks promote prosperity, and improve the morals, order, comfort, and convenience of
the County and its inhabitants.
way s0 i that slid h0
published in said purist;
proper and not in any suppleme, NOW, THEREFORE, BE IT ORDAINED by the Board of County Commissioners of the
reof ,
tne , and that the first County of Weld• State of Colorado, that the following Undesirable Weed Management
tpublication of Plan is hereby adopted for all of the unincorporated lands within the County of
said notice as Weld. State of Colorado, to take effect upon the effective date of this Ordinance
aforesaid& Was on the and that the enforcement provisions contained herein shall apply to all persons
�, who are required to control undesirable plants within the unincorporated areas
-� n of the County of Weld• State of Colorado, pursuant to t¢e provisions of the Plan.
day al�I '' i 19 '1 �--
a ,
and the last on the day of
r
f
1
tom -@, ; 1:) , A 1 I
Subscribed and sriorn to before ''
me this ..day of. hew/
19„7. tt Atntia, ft re-
My Commission Expires Marh IS, 1996,
YTICLE I - UIQE$Z*AILE PLANT MAMAOSSIBMT PLAN
I. Introduction
A. Description of NB 90-1175, Undesirable Plant Management Act
The Undesirable Plant Management Act which was signed into law on
May 7. 1991 (CRS 35-5.5-101, at. seq.), states that certain
undesirable plants pose a threat to the continued economic and
environmental value of the land in Colorado and that they must be
managed by all landowners in the state. The undesirable plants
designated for mandatory management statewide are; leafy spurge
(Ruphorbia esula), Russian knapweed (Centaurea repens), diffuse
knapweed (Centaurea diffuse) and spotted knapweed (Centaurs.
maculosa). Additional weed species may be added to the state list
by each local jurisdiction.
The law states such that local governments (cities and counties) are
directed to take the necessary steps to manage the undesirable .
plants in their respective jurisdictions. They are further directed
to appoint an advisory commission whose responsibilities are
threefold:
1) develop recommended management criteria and integrated weed
management plans for managing the designated undesirable
plants;
2) recommend addition of undesirable plants that shall be subject
to integrated management;
3) recommend to the County Commissioners those landowners who
shall be required to submit integrated weed management plans
for managing the undesirable plants on their property.
The law further states that by January 1, 1992, each local governing
body is to have developed and adopted an Undesirable Plant
Management Plan for all lands within its jurisdictional boundaries.
II. Description of the County Weed Problem
A. Need Species in Weld County to be Controlled Pursuant to Weed
Control Laws
The Pest Control Districts Law (CRS 35-5-104) enabled landowners in
each County the ability, through a lengthy petitioning and balloting
process, to establish weed control districts. Within each weed
district, designated species are mandated to be controlled. In Weld
County, 9 Such weed districts exist. The districts occur in the
lower 2/3 of the county, and the weed species designated for control
ranges from 3-7 species depending upon the,weed district. The weed
species that are currently being managed in at least a part of Weld
County are as follows:
Leafy spurge (Euphorbia esula), Canada thistle (cirsium
arvense), musk thistle (Carduus nutans), field bindweed
(Convolvolus arvensis), whitetop (Cardaria draba), Russian
knapweed (Centaurea repens) and wild prose millet (Panicun
miliaceum).
Under the Undesirable Plant Management Act (CRS 35-5.5-101. at seq)
there are four weed species which are mandated for county-wide
management. They are leafy spurge, and Russian, diffuse and
spotted knapweeds. Canada thistle and musk thistle have been added
to the County-wide undesirable plant list by the Weld County
Commissioners, in accordance with CRS 35-5.5-108(3).
.y
of the weed species listed previously, Canada thistle, field
bindweed, leafy spurge, musk thistle, Russian knapweed, whitetop and
wild prose millet cover the most acreage in Weld County and pose the
greatest economic and environmental threat to the county. Diffuse
knapweed is currently localised to a few drainages and rights-of-way
in the southwest part of the County, and there are no known spotted
knapweed infestations in the County.
III. Objectives and Goals
• A. Statement of Objectives
The objectives of the Weld County Pest and Weed Department are
fourfold:
1. Develop and carry out a comprehensive noxious weed control
program on all County right-of-way and other County property,
such as in sand and gravel mining operations, grader shed lots
and open space areas.
2. Establish an educational program, by using mailings and
holding educational and calibration seminars, that will
effectively communicate weed management information to the
landowners in the County.
MN 7, N92
3. Identify non-informed or negligent landowners who are not
carrying out weed management programs on their property and
provide technical support for establishing weed management
plans or enforce on properties, if necessary.
4. Work with ,all state and federal agencies, through
intergovernmental agreements, if necessary, towards
establishing effective weed management programs on their
property.
B. Short Term Goals (1-3 years)
1. Map all the County roads for noxious weed infestations.
2. Map on a computer program (Design CADD) at least half of the
landowners that have leafy spurge, Canada thistle and Russian
knapweed infestations.
•
3. Establish contact with every landowner on the South Platte and
Poudre Rivers that have leafy spurge. -
4. Establish 5-5 educational/calibration seminars (annually) that
work directly with 150-200 landowners each year.
5. Have established contact with the Colorado Department of
Highways, Dept. of Parks and Recreation, Colorado Land Board,
Division of Wildlife and U.S. Forest Service. Help them
develop Weed Management Plans and where appropriate enter into
cooperative intergovernmental agreements.
6. Have established 6-8 biological control release sites
throughout the County.
7. By the fourth year have reduced the noxious weed acreage
sprayed on County right-of-way by 15-20X.
C. Long Term Goals (4-8 years)
1. Have mapped on the computer program all the noxious weed
infestations countywide, including private, state and federal
lands.
2. Have reduced the noxious weed acreage sprayed on County right-
of-way by 40-50X.
3. Have contacted and worked with every landowner county-wide who
has a noxious weed infestation.
4. Have established 30-50 biological control release sites in the
County.
IV. Plan of Work - Implementation
A. Description of Integrated Weed Management Techniques
The weed species 'designated as undesirable and mandated for
management are leafy spurge ( uphorbia SSula), Russian knapweed
(Centaurea rename), diffuse knapweed (Centaurea diffuse). spotted
knapweed (Centaurea maculosa), Canada thistle (Cirsium arvense) and
musk thistle (Carduus nutans). Integrated weed management methods
are to be used in managing these weed species (CRS 35-5.5-107).
Integrated management techniques include education; preventive
measures; and control measures including cultural, mechanical,
biological and chemical c0ntrol.__For the purposes of this plan the
following definitions for the control measures will be used.
1. Cultural control means those methodologies or management
practices conducted to favor the growth of desirable plants
over undesirable plants, including but not limited to
maintaining an optimum fertility and plant moisture status in
an area, planting at optimum density and spatial arrangement
in an area, and planting species most suited to an area.
2. Mechanical control means those methodologies or management
practices that physically disrupt plant growth, including but
not limited to tilling, mowing, burning, flooding, mulching,
hand-pulling and hoeing.
3. Biological control means the use of organisms such as sheep,
goats, cattle, insects and plant diseases to disrupt the
growth of undesirable plants.
4. Chemical control means the use of herbicides or plant growth
regulators to disrupt the growth of undesirabre'-plants.
Management of the various undesirable plants will vary depending
upon the site the plant is located in. Management options for each
weed species will be developed for each site where the plant is
found in Weld County.
The integrated management options listed below are meant to provide
various management techniques for controlling the noxious weeds in
the various environmental sites they are found. By no means are all
the management options developed. Additional combinations of
management techniques are possible which may be submitted by private
landowners. The integrated weed management plans submitted by
individual landowners will be evaluated
Vegetation Management Specialist by the Wald County
gand the Integrated Weed Management
Advisory Commission on a case b by case basis.
Integrated'weed Management Options for Each Weed Species
Leafy Spurt', Leafy spurge is a deep rooted perennial plant that
spreads by seeds anti creeping roots. It has a vast underground root
system which makes it difficu}t to control with any one central
technique. Leafy spurge is found primarily in riparian sites (along
waterways such as the Poudre and South Platte Rivers) in Weld County
and also along irrigation ditches, range and pastures, roadsides and
other non cropland sites.
1. Control Measures
a. Cultural Control, Seeding perennial grasses and forts
can be an effective management tool. Early emerging
plant species that utilize early season moisture such as
smooth:brows (Bromus inermis) or created wheatgrass
(Agropyron cristatum) have reduced leafy spurge density
and limited the spread and establishment of new
infestation. Sequential glyphosate applications
followed by a seeding of Luna Pubescent Wheatgrass,
Ephraim Crested Wheatgrass, Intermediate Wheatgrass,
Sharman Big Bluegrass or Bozoisky Russian Wild Rye has
May 7, 1992
shown to be very effective in reducing an existing stand
of leafy spurge.
b. Mechanical Control: Mechanical control of leafy spurge
is difficult at bast, however. repeated mowing every 14-
21 days throughout the summer. starting before flowering
stage, will at least keep the plants from going to seed
and may reduce the underground root reserve. Research
results are not available to indicate whether stand
reduction or eradication could be achieved through use
of this technique. •-
c. Biological Control: Grazing with sheep and goats
throughout the spring, sunnier, and fall will keep leafy
spurge from going to seed and may reduce the underground
root reserve. This practice may also weaken the plants
to make them more susceptible to chemical control.
Several insect species that have been released by the
USDA in the United States are showing some control of
leafy spurge. Two species of flea beetles, Apthona
flava and Apthona nigriscutis feed on leafy spurge.
Adults feed on the foliage during the summer and the
larvae burrow through the soil and mine the roots and
fine root hairs. These insects used alone may not
control leafy spurge. When used along with other
,insects such as Spurgia esula, a gall midge which feeds
on the flowers preventing seed production, they will
weaken the plant and make it more susceptible to other
control methods, particularly chemical control.
d. Chemical Control: , There are„a number of herbicides
labelled for use on leafy spurge. Those that can be
used independently or in combination with each other
are: picloram (Tordon), dicamba (Banvel), 2-4-D (many
different formulations), glyphosate (Roundup and Rodeo)
and fosamine (granite).
2. Integrated Management Options by site
a. Range, Pasture and Riparian Sites
Option'p1 Biological and Chemical Control: Grazing with
sheep or goats from early April through late August -
early September followed by a herbicide treatment in
late September - early October.
Option #2 Biological and Chemical Control: The release
of insects such as Apthona nigriscutis, Apthona Playa
and/or Spurgia esula can be made. A herbicide treatment
can then be made during the true flower stage (where
insects were not released) and in the fall where insects
were released. Herbicide applications should only be
carried out in the fall, where insects are used. Use of
herbicides at different times of the growing season can
be instituted as additional IPM research is conducted
and recommendations are developed.
Option 03 Mechanical and Chemical Control: Mowing can
be carried out throughout the season with the first
mowing cycle at the bud stage. Mowidg` should step
during late August followed by a herbicide treatment
during late September-early October, before a hard
freeze.
Option #4 Biological or Mechanical Control Only: The
use of sheep or goats or mowing should be used all
season to keep leafy spurge from going to seed. Whether
this method will keep the existing infestation from
spreading by underground root growth is uncertain.
Option #5 Chemical Control Only: Herbicides should be
used in the spring, early summer during the true flower
stage and in the fall just before a hard freeze. Only
the herbicides labelled for the site intended will be
used.
b. ng Irrigation Ditches
Option #1 Biological and Chemical Control: The release
of insects such as Apthona nigriscutis, Apthona (lava
and/or Spurgia esula could ,he made. A herbicide
treatment should be carried out at the true flower stage
(if the Spurgia esula has not kept the plants from going
to seed) and/or in the fall just before a hard freeze.
Option #2 Chemical Control Only: Herbicides can be used
in the spring-early summer during the true flower stage
and in the fall just before a hard freeze. Only the
herbicides labelled for the site intended will be used.
c. Road Right-of-Ways and Other Non-Crop Areas
Option #1 Mechanical and Chemical Control: One mowing
cycle can be carried out at the bud to early flower
stage. A herbicide application should be made at the
true Flower stage.
Option #2 Chemical Control Only: Herbicides can be used
in the spring-early summer during the true flower stage
• and in the fall just before a hard freeze. Only the
herbicides labelled for use on roadsides and other non-
cropland areas would be used.
Russian Knapweed: Russian knapweed is a non-native perennial plant
that spreads by seeds and creeping roots. It has the ability to
release chemicals into the environment as foliage decays which
inhibit the growth of surrounding vegetation (allelopathic
properties). Thus, once established Russian knapweed can colonize
an area rapidly. Russian knapweed is found primarily in range and
pastures, roadsides and other non-cropland sites in'Weld County.
1. Control Measures
a. Cultural Control: Seeding perennial grasses such as
smooth brow' (Bremus ieermisl will help to compete with
Russian knapweed and slow its spread. In addition,
stimulating grass growth by fertilizing and/or
irrigation should increase grass competition. Due to
the allelopathic properties of Russian knapweed, other
control techniques such as judicious chemical control
would have to be implemented in order to give grasses a
chance to compete.
b. Mechanical Control, Mechanical control of Russian
knapweed could be carried out throughout the smmar with
, repeated mowing every 14-21 days. This would at least
keep Russian knapweed from going to seed. Whether this
control technique will reduce the root mass and
-subsequently reduce an existing stand is not known.
c. Biological Control,: There are, currently no biological
control agents available for Russian knapweed.
d. Chemical Control: There are a number of herbicides
labelled for use on Russian knapweed. Those that can be
used independently or in combination with each other
are: chlorsulfuron (Telar), picloram (Tordon), 2-4-➢
(many different formulations) and glyphosate (Roundup •
and Rodeo).
2. Integrated Management Options by site.
a. Range and Pastures
Option #1 Mechanical and Chemical Control: Mowing can
be carried out throughout the season with the first and
successive mowing cycles carried out at the bud stage.
A herbicide treatment can then be made in the fall
before a hard freeze.
Option #2 Cultural and Chemical Control: A herbicide
application, using short residual herbicides such as
glyphosate and/or 2-4-D, can be made followed up by
reseeding with a competitive grass such as smooth brome
or other sod forming species. In addition,
fertilization or irrigation could be instituted to
stimulate increase grass growth.
Option #3 Chemical Control Only: Herbicide applications
can be made to Russian knapweed during the bud stage,
bloom to post-bloom and/or in the fall, depending upon
herbicide used.
b. Road right of way and other non-crop areas.
Option s1 Mechanical and Chemical Control: One mowing
cycle tan be carried out at the bud to early flower
stage. A herbicide application can be made during the
bud stage, bloom to post-bloom and/or in the fall,
depending upon the herbicide used.
Option #2 Cultural and Chemical Control: Use of short
residual herbicides such as glyphosate and/or 2-4-0 can
be used in the early summer during the bud stage.
Seeding with perennial grasses such as smooth brome,
Luna Pubescent Wheatgrass, Ephraim Crested Wheatgrass,
Intermediate Wheatgrass, Sherman Big Bluegrass or
Bozoisky Russian Wild Rye can than be carried out later
in the summer, at the appropriate time.
Option #1 Chemical Only: Herbicide applications can be
made during the bud stage, bloom to post bloom and/or in
the fall, depending upon the herbicide used.
Diffuse Knapweed: Diffuse knapweed is a non-native, biennial to
short lived perennial forb that reproduces by seed. It spreads
rapidly by the mature plant breaking off at ground level and being
blown with the wind, dispersing seed. It is a pioneer species that
will quickly invade disturbed, dry sites. Diffuse knapweed is found
in the southwest part of Weld County along rights-of-way, dry
pasture sites and in gravelly riparian sites, such as along Boulder
Creek and the St. Vrain and South Platte Rivers.
1. Control Measures
a. Cultural Control: Cultural Control of diffuse knapweed
is similar to Russian knapweed in that seeding with
perennial grasses such as smooth brome and crested
wheatgrass will help to compete with diffuse knapweed
and slow its spread. Seeding alone in infested sites
will not, however, control the existing stand.
b. Mechanical Control: Mowing diffuse knapweed when it is
in the bud stage and again when it is flowering can
significantly reduce seed production. Keeping diffuse
knapweed from going to seed over a number of years can
eventually eliminate an infestation, once the seed
source in the soil is depleted.
c. Biological Control: Two species of picture-winged
flies, Urophora affinis and U. guadrifasciata have
demonstrated the ability to reduce the seed production
of diffuse and spotted knapweed. The flies lay eggs on
the developing seed heads. As a result of the larvae
feeding an the flowering heads, the plants produce galls
which reduces seed production. The Colorado insectary
is currently rearing these two flies and has made
releases in the state the last 3 years.
d. Chemical Control! There are a few herbicides labelled
for use on diffuse knapweed. Those that can be used
independently or in combination with each other are:
picloram (Tordon), dicamba (Banvel), glyphosate
(Roundup), and 2-4-D (many different formulations).
2. Integrated Management Options by site
a. Pasture and riparian areas
Option, N1 Cultural and Chemical Control: A herbicide
application can by made in pprly summer when diffuse
knapweed is in the rosette through bolting stage.
Reseeding with competitive perennial grasses such as
smooth brome and crested wheatgrass can be followed
later in the summer depending upon the herbicide used
and rate of application.
Option #2 Biological and Chemical Control: The release
of insects such as Urophora affinis and U.
n adrifasciata can be made. A herbicide treatment can
than be made from the rosette through bolting stage
(whet-4 insects were not released) and in the fall where
insects were released. Herbicide applications should
only be carried out in the fall, where insects are used.
Use of herbicides at different times of the growing
season can be instituted as additional IPM research is
conducted and recommendations are developed.
The`lte#Newa Pape M. - '7:1932
Option 03 Mechanical end Chemical Control, Mewing can - Option R2 Mechanical and Chemical Controls Mowing can
be carried out when diffuse knapweed is in the bud stage
be carried out throughout the season with the first
and again ftowerythat
A herbicide application can
then be made to any plants Char have nboltad, if mowing cycle sn bud st by Meig should stop
necessary. during late followed by a herbicide treatmente
during late September through October, before a hard
freeze.
Option Wa Mechanical Control Only: Mowing can be,
carried out throughout the season, reducing seed Jset. Option e3 Cultural and Chemical Control: A herbicide
application, using short residual herbicides such as
Option #5 Chemical Control Only, Herbicide application
can be made during the rosette stage, seemor fall, glyphosate and/or 2-a-D, can be made followed up by
seeing reseeding with a competitive grass such ac smooth brome
and while bolting. or other sod forming species. In addition,
fertilization or irrigation could be instituted to
b. Right-of-Ways and other non-crop areas stimulate increase grass growth.
Option 41 Cultural and Chemical Controls Same as for Option Aa Chemical Control Only, Herbicide applications
Option W1 in Pasture and Riparian Areas. can be made to Canada thistle from rosette to the bud
Option W2 Mechanical and Chemical Controls One mowing stage, and/or in the fall, depending upon the herbicide
used.
operation can be carried out when diffuse knapweed is in _
the bud stage. If necessary, a herbicide application
can be made to plants that have rebolted. . Road Right-of-Ways and other Non-Crop Areas
Option 03 Mechanical Control Only: Same as for optionOptiop 01 Mechanical and Chemical Control: One mowing
Wa in Pasture and Riparian Areas. cycle can be carried out at the bud to early flower
stage. A herbicide application can be made from rosette
'Option Wa Chemical Control Only, Same as for Option WS to bud stage andlor in the fall, depending upon the
' in Pasture and Riparian Areas. herbicide used.
Spotted Rnapweed: Spotted knapweed is a non-native, perennial forb Option 02 Cultural and Chemical Controls A herbicide
that reproduces by seed. It is a highly competitive plant in application can be made in early summer when Canada
rangeland sites that will exclude most grasses and !orbs with time. thistle is in the rosette through bud stage. Reseeding
Thera are currently no known spotted knapweed infestations in Weld with competitive perennial grasses such as smooth brome
County. and crested wheatgraas can be followed later in the
summer depending upon the herbicide used and rate of
1. Control Measures application.
a. Cultural Controls cultural Control of spotted knapweed Option 01 Chemical Control Only: Herbicide applications
is similar to Russian and diffuse knapweed in that can be made from rosette to bud stage, and/or in the
seeding with perennial grasses such as smooth brume end fell, depending upon the herbicide need.
created wheatgress will help to compete with spotted
• knapweed and slow its spread. Seeding infested sites c. Cropland Sites
will not, however, control the existing stand. In range
and pasture conditions. good grazing management Canada thistle is found in almost every crop grown in
practices will help to reduce the spread of the Weld County. Prescription weed management measures
knapveeds in general. developed by the csu weed scientists and the Weld County
Extension Agronomist will be used.
b. Mechanical Control, Mechanical control of spotted
knapweed could be carried out throughout the summer with Musk Thistle, Musk thistle is a biennial plant that reproduces only
repeated mowing every 1a-21 days. This would at least by seed. Rosettes (clump of leaves on the ground) are formed during
the first year of growth andprolific seedhe and 'Sets seed the
h a single plant
keep spatted knapweed from going to seed. Whether this second year. It is a producer
pwae producing up to 26,000 seeds. Musk thistle is found primarily in
control technique u will reduce the root mass and pastures and riparian situ '(along wat'Crwaye such as the South
subsequently reduce an existing stand is net known.
Platte, St. Vrain, Big Thompson, and Little Thompson drainages and
c. Biological Control: The same as what was developed
and other no-crop areas.
Boulder Creek) and along irrigation ditches, roadside rights-of-way
under biological control for diffuse knapweed.
d. Chemical Control, There are a few herbicides labelled 1. Control Measures
for use on spotted knapweed. Those that can be used a. Cultural Control: Maintaining pastures and riparian
independently or in combination with each other a sites in good condition is the primary method of
pifferen (-cordon). dicamba (Banval).- +2-A-D (many culturally managing musk thistle. Promoting good grass
different formulations and clopyrald and 2-4-D growth by proper grazing management and fertilizing
(Curtail)• according to soil testing recommendations will prevent
establishment of muck thistle.
Canada Thistle: Canada thistle is an aggressive, creeping perennial
that reproduces by seed and vegetative buds in the root system. It b. Mechanical Control, Musk thistle can be effectively
is a difficult plant to,control because of its extensive rootcontrolled mechanically. Severing
the roots below
System. Vertical roots may grow 6-15 foot deep and horizontal roots ground with a shovel or hoe or mowing musk thistle every.
may extend 15 feet or more. Canada thistle is the most widespread time it reaches early flower stage will radars, if not
noxious weed in Weld County. It can be found in most habitat types
including, pastures, riparian sites (along waterways such as the eliminate, seed production. If mowing occurs mid to
Poudre, South Platte, St. Vrain and Big Thompson Rivers), Irrigation late flower stage the thistle should be gathered and
ditches, along roadside rights-of-way and in the various crop and burned to destroy any seed that has developed.
non-cropland sites.
c. Biological Control: Two species of weevils, Rhinocyllus
1. Control Measures conicus (seed heed weevil) and Trichosirocalus horridus,
attack two different sites of musk thistle. The seed
a. Cultural control: plant competition from various head weevil, as its name implies, attacks the seeds of
grasses and from alfalfa can be an effective management musk thistle. Eggs are laid by the female on the back
tool. Early emerging grass species such as smooth brome of developing flowers and then the larvae bore into the
and coasted wheatgrass can be used to compete with flower, destroying the developing seed. The seed head
Canada thistle area slow the spread and establishment of weevil can reduce seed production by as much as 505.
new infestations. competition alone, however. Is seldom Use of this weevil as the sole means of controlling musk
effective on Canada thistle. thistle is not very effective.
b. Mechanical Control: Mechanical Control of Canada Trichosirocalus horridus attacks the crown area of musk
thistle could be carried out throughout the summer with thistle rosettes, killing dr weakening the plant before
repeated mowing every 14 days. This would keep Canada it bolts. Use of both weevil species together may prove
thistle fromgoing to seed; however. mowing has shown to to be an effective biological control program.
stimulate new shoot growth from roots. Consequently,
.mowing alone may increase shoot density in en d. Chemical Control, There are a number of herbicides
established stand. Whether consistent mowing for labelled for use n Musk thistle. depending upon where
consecutive years (2-3 years) will reduce the root mass the thistle is round. The herbicides that ran be used
and subsequently reduce en existing stand is unknown. independently or in combination with other compounds
picloram (Tordon). dicamha (Benue!), 2-a-D (many
c. Biological Control: There is one insect species, a different formulations), chlorsulfuron (Telar).
weevil. called Ceutoienchus litura,-that is currently etepyrelid (curtail. stinger, Transline) and glyphosate
being used as a biological control agent on Canada (Roundup, Rodeo).
thistle in Colorado. The female lays eggs on the
underside of the leaves in early spring and then the 2. Integrated Management options by Site
larvae bore into the main leaf vein and migrate down to a. Pasture and Ripariap Sites
the erown of the plant. The holes created by the larvae
open up Canada thistle to secondary infection. Where Option Cl Biological and Chemical Control: Release of
high numbers of the larvae occur death of Canada thistle Trichosirocalus horridus can be made at the appropriate
can occur. time of the summer. Rhinocyllus conicus is well
established in Weld County and should already be
d. Chemical Control, Theca umber of herbicides infesting the stand. A herbicide application can then
labelled for use on Canada thistle,depending upon where be made to musk thistle at the flower stage. Telar or
the thistle is found. The herbicides that can be used Escort should be used when treating musk thistle in the
independently or in combination with other compounds ' flower stage. Herbicide applications should only be
picloram (Tordon), dicamba (Banvel);2-a-0 (many carried out in the flower stage in order to allow the
different formulations), chleraulfuren (Telar), seed head weevil to complete its life cycle. Use of
clopyralid (curtail, Stinger, Transline) and glyphosate herbicides to rosettes in the spring or fall should not
(Roundup, Rodeo). - be carried out where Trichosirocalus horridus was
released. Use of herbicides at different times of the
2. Integrated Management Options by Site growing season can be instituted as additional IPM
research is conducted and recommendations are developed.
a. Range, pasture and Riparian Sites
•
Option Cl Biological and Chemical Control: Release of
the insect Ceutarynchus liters can be made during the
early summer. A herbicide application can then be made
at the bud stage (where insects were not released) and
in the fall where insects were released. Herbicide
applications should only be carried out in the fall,
•
where insects were directly released. Use of herbicides
at different times of the growing season can be . god-A.ov
'instituted as additional IPM research is coordinated and
-7, -
Option s2 Mechanical end Chemical Control; Mowing can
be carried out throughout the summer when musk thistle
is in the bud to early flower stage. A herbicide
application can than be made in October to the fall
rosettes and any bolted plants.
Option IS Mechanical Control Only: Mowing can be
carried out throughout the summer when musk thistle is
in the bud to early flower stage, keeping it from
producing seed. If mowing occurs mid to late flower
stage the thistle should be gathered sad burned to
destroy any seed that has developed.
Option #4 Chemical Control Only, Herbicides can be used
in the spring and fall When the plant is in the rosette
stage. Only the herbicides labelled for the site
intended will be used. .
b. Road Right-of-Ways and other Non Crop Areas
Option #1 Biological and Chemical Control; Same as for
option 01 in Pasture and Riparian sites.
Option #2 Mechanical and Chemical Controls One mowing
pass can be made when musk thistle is in the bud to
early flower stage. A herbicide application can be made
in the fall to the rosettes and rebolted plants.
Option #3 Chemical Control Only: Herbicides can be used
in the spring and the fall when the plant is in the
rosette stage. Only the herbicides labelled for the
site Intended will be used.
C. Prevention Measures
Preventive control means using measures which will stop or forestall
weeds from contaminating an area. Establishing preventive measures
are often the most practical and cost effective means of weed
control.
The preventive measures which seem most practical for Weld County
are as follows, 1) establishing weed free seed and mulch
requirements for.,reclamation of disturbed sites, 2) promoting the
Colorado Weed Free Hay and Forage program, 3) prioritizing weed
management areas along routes of dispersal, and 4) identifying
noxious weed species in counties bordering Weld County.
1. Weed Free Seed and Mulch Standards
Where the ground is disturbed by activities, such as road
preparation for road resurfacing, sand and gravel lot
operations and oil and gas well operations, weeds will be the
first plants to colonize or revegetate the site. It is
important that these sites be reclaimed so that noxious weeds
do not become established.
Weld County will establish standards for using weed free seed
and mulch on all county operations concerned with the
reclamation of disturbed sites, such as on roadside
resurfacing projects and sand and gravel lot operations.
Additional regulations may be considered for similar
operations being carried out on private land.
2. Weed Free Hay and Forage Program
Standards are currently being developed that will enable
growers the ability to have their hay and forage certified as
noxious weed free. These standards will encourage growers to
produce noxious weed free hay and forage so that it can be
shipped and used anywhere in the U.S. (particularly where
noxious weed free standards currently exist).
The Weld County Vegetation Management Specialist will provide
an inspection and certification service and will promote the
Colorado Weed Free Forage Standards, through the use of
seminars, radio spots and newspaper articles.
3. Prioritizing Weed Management Areas Along Routes of Dispersal
Weeds are spread rapidly through the dispersal of weed seeds
in air and water. Consequently, high weed seed dispersal
areas are associated with right-of-ways, such as along all
roads and railroads and along waterways, i.e., along the
Poudre, South Platte, St. Vrain and Little Thompson Rivers and
irrigation canals.
The County Pest and Weed Department will carry out a noxious
weed control program on all county roads from May through
September. - The noxious weeds targeted for control include;
Canada, musk and bull thistle; leafy spurge: Russian, diffuse
and spotted.knapweed; field bindweed; whitetop; and wild proso
millet. In addition, contact will be made with the Colorado
Department of Highways, all irrigation and ditch companies in
the County and the Union Pacific, Burlington Northern and
Great Western Railroad companies. Information regarding the
Undesirable Plant Management. Act will be distributed and their
cooperation will be encouraged. Assistance in helping them
develop their integrated weed management programs will be
offered. ...___
In working with landowners on private property, all lands
bordering the rivers in the county will be considered high
priority areas. ;Landowner compliance with the Undesirable
Plant Management Act will be encouraged.
4. Identifying Noxious Weeds in Bordering Counties That Do Not
Occur in Wald County
Contact will be mad, with the weed control departments in the
bordering counties to identify the noxious weed species which
occur in each county that would threaten Weld County. Plans
will be developed to monitor the borders of Weld County, as
necessary.
D. Educational Programs -
Education of the public is one of the most important components of
a Weed Management program. Emphasis will be placed on continuing a
multifaceted educational program. The following programs have been
instituted in the past and will continue to be conducted every year.
1. Timely newspaper articles concerned with weed identification
and management.
2. Timely radio broadcasts following the information in the
newspaper articles.
3. Conducting lagdowner weed management seminars and calibration
workshops.
The Nov •
4. Having an educational booth at the Colorado Farm Show,
5. Utilizing brochures and SIA's to hand out to /individual
landowners.
E. Mapping
Establishing an accurate baseline map of the existing noxious weed,
infestations in the county is extremely important for the ongoing
evaluation of the- effectiveness of the county weed management
program. Therefore, a computerized mapping program will be
established that will map the noxious weeds established in Weld
County.
County roadsides will be mapped using a computer and
printer/datalogger on the spray equipment. Private and state land
will be mapped by Pest and.Weed Department personnel taking aerial
•
maps from the County Assessor's Office into the field and mapping on
site. Through the use of the Design CADD computer mapping program
and a digitizer, the noxious weed infestations will be mapped. All
mapping information will be stored in the county IBM computer
systems and can be retrieved for future evaluation.
F. Establishing Cooperative Intergovernmental Agreements •
Contact will be made with the following agencies. concerning
compliance with the Colorado Undesirable Plant Management Act.
1. Colorado State Department of Highways
2. Colorado State Department of Parks and Recreation
3. Colorado Division of Wildlife •
4. Colorado State Land Board
5. U.S. Forest Service
Assistance will be offered in helping each agency develop integrated
weed management plans for their lands. Actual assistance in
carrying out the weed control programs on their properties will also
be offered. Cooperative intergovernmental agreements tan be
established if Weld County is asked to assist in implementing the
weed control•measures.
G. Adopt a Roadside Program
An Adopt a Roadside Program will be established which will give
landowners the ability to take the responsibility to manage the
noxious weeds on the county rights-of-way that borders their
property.
Landowners who are chemically sensitive or for some reason do not
want chemicals sprayed or mowing activities carried out along their
- property, can take the responsibility for managing the nosiest. wade-
on the roadside right-of-way. Landowner agreements With specific
requirements for compliance will be established.
K. iALoreameat se Privets ad Peelle Property
Cooperation from all landowners (private asd state) Will be
encouraged through positive communication by mail and through
personal contact. When weed control measures are not tarried-out by
a landowner, enforcement measures may have to be instituted. A11"
procedures as established by the Undesirable Plant Management Law,
CRS 35-5.5-109, the Pest Control Districts Law. CRS 35-5-108, and
any and all federal, state, and local regulations will be followed,
for enforcement on private or public property. Integrated weed
management plans will be requested from certain landowners, as
determined by the county vegetation management specialist and the
Undesirable Plant Management Advisory Board. Work priorities must
be established due to the size of the county and the number of
landowners with existing noxious weed problems. The following list
prioritizes where enforcement activities will be carried out in
ranking order of importance. ,
1. Lands bordering all waterways (rivers and irrigation ditches).
et.
2. Complaint properties.
3. Landowners identified asnegligent in the past.
4. Landowners with 5 or more acre; of noxious weeds.
V. Evaluation of Program
The goals and the plan of work established in chapters 3 and 4 of this
document will be reviewed and evaluated at the end of every year. A
written evaluation will be prepared establishing additions or changes in
the plan of work for the following year. Any additions or changes shall
be approved by the Undesirable Plant Management Advisory Board and the
Board of County Commissioners.
The Weld County Undesirable Plant Management Plan shall be reviewed and
amended, as needed, at least every three years (CRS 35-5.5-107(4)(a)).
VI. No Waiver of Immunities/No Creation of Duties. Standard of Care, or Rights
for Third Parties
No portion of this Undesirable Plant Management Plan shall be deemed to
constitute a waiver of any immunities which Weld County, Colorado, by and
through the Board of County Commissioners of Weld County, or any pest
control districts and/or their Boards, or the Weld County Undesirable
Plant Management Advisory Commission or their officers or employees may
possess, nor shall any provision of this Plan be construed to create any
duty, standard of care or rights in favor of any third parties with the
respect to any obligation created by this Plan.
ARTICLE II - ENFORCEMENT OF UNDESIRABLE PLANT MANAGEMENT PLAN
Section 1 - Authorized Agent for Enforcement: Pursuant to Section
35-5.5-105(2) CRS, the Weld County Vegetation Management
Specialist, his employees and agents, are hereby authorized to
enforce the above stated Undesirable Plant Management Plan in the
unincorporated areas of County of Weld, State of Colorado, by
utilizing those procedures set forth in Section 35-5-108, .CRS,
Section 35-5.5-109, CRS, and any and all applicable. State and
t
°f( ail 4P?P°P WI PP! tA3 38 +#ww..i 3.17?,i1.4
18141.1814.1388.Rp4 0.2" ,: .,fi: tr-r-4'<,.r:;ygs:9 medf;rssagi
lie Ngw ang ps.f
Federal ltetltea, rules, regulations, and ordinances, including the
rwaiming provisions of this Ordinance No. 169.
settien 2 - litbt of Intry: Prior to entering private lands for the
purpose of enforcing- the Weld County Undesirable Plant Management
Plan, the Weld County Vegetation Management Specialist shall first '
obtain a "right of entry" from the Board of County Commissioners, no
less than ten days after a Notice to Control Identified Undesirable .
Plants has been sent to the owner or occupant of the private lands
and said owner or occupant has failed to comply with said notice.
ra-
' Section 3 - Mailing of Assessments: All assessments for the whole
cost of any enforcement work performed by the Weld County Vegetation
Management Specialist or his designee(s) upon private lands,
including up to 1$X for inspection and other incidental costs in
connection therewith, shall be mailed to the landowner or occupant
by certified mail. Failure to receive said assessment shall not act
as a defense to said assessment.
Section 4 - Failure to Pay Assessment: Any assessment which.is not
paid within thirty-three days after the date of mailing by certified
mail to the landowner or occupant of private lands upon which the
Weld County Vegetation Management Specialist or his designee(s) have
performed enforcement work, shall constitute a lien against each lot
or tract of land until paid and may be certified by resolution of
the Board of County Commissioners to the Weld County Treasurer's
Office to be collected in the same manner as provided for collection
of taxes upon the'private lands in accordance with Section 35-5.5-
109 (5)(a), CRS.
ARTICLE III - SEVERABILITY
Section 1. If any section, subsection, paragraph: sentence, clause
or phrase of this Ordinance No, 169 is, for any reason, held or
decided to be invalid or unconstitutional, such decision shall not
effect the validity of the remaining portions.
evert of County Commissioners Weld County, Colorado,
;e't lane that it would have passed this Ordinance No. 169,
t w y Uwe d every section, subsection, paragraph, sentence,
these irrespective of the fact that any one or
more seetins. suheeet4ees, paragraphs, sentences. clauses, or
phrases might s, 'flared to be unconstitutional or invalid.
ltTICLE IV - LIABILITY
This Ordinance No, Ito shell not be intended to create a civil cause of
action against the Board of Getty Commissioners Weld County, Colorado, or any
other person that may administer this Ordinance No. 169 in any manner.
ONOINANCE 169 - ONDEBInA1ti PLANT MANAOEMENT
PACs 22
ARTICLE V - EFFECTIVE DATE
BE IT FURTHER ORDAINED by the Board of County
Colorado, that this Ordinance No. 169 shall become effective five days ounty Commissioners of Weld County,
final public notice. in accordance with Section 3-14 (2) of the Weld County Home
Rule Charter, ys after its
The above and foregoing
Ordinance No. 169 was,by the following vote on motion duly made and
seconded, adopted
on the 4th day of May, A.D..) 1992.
ler
ATTEST: / 2A2/ BOARD OF Co
44/159d
BOAR CO CYUNTY COMMISSIONERS
Weld County Clerk to , COLORADO
the Board
G11"en Ken dy, airman BY:
Deputy Clerk to the Boar EXCUSED
Constance L. Harbert, Pro-Tem
•
APPROVED AS T FORM:
i
C. W. Ki
County Attorney
Gor . Lac
W. . Wes r
FIRST READING:
MPUBLICATION,
March 11, 1992
March 12, 1992
SECOND READING:
PUBLICATION: March 23, 1992
March 26, 1992
FIRST READING, REVISED:
PUBLICATION: April 6, 1992
April 9, 1992
SECOND READING, REVISED: April 20, 1992
PUBLICATION:
April 23, 1992
FINAL READING. REVISED:
PUBLICATION: May 4, 1992
May 7, 1992
EFFECTIVE DATE:
May 12, 1992
Hello