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BURRWEED, LAWN
Burrweed, Lawn (Spurweed)
[Soliva sessilis Ruiz & Pavón]
DESCRIPTION
Lawn
burrweed, also known as spurweed, is a very low-growing winter annual weed that
closely resembles parsley-piert and knawel. It is freely branched and usually
does not root at the nodes. The leaves are oppositely arranged and highly
divided into little leaf segments. Flowers are small (1/4 inch or less), broad,
and inconspicuous. The seeds have sharp spines, hence the common name. Lawn
burrweed is commonly found in turfgrass systems. Infestations are increasing in
North Carolina, particularly in the southern Coastal Plain and Piedmont.
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Characteristic
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Description
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Growth Season
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winter annual weed
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Growth Habit
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prostrate, spreading
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Leaflet Number
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one
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Leaf Margin
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three-lobed with each lobe again divided into lobes
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Leaf Hairs
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upper/lower surface; sparsely hairy
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Leaf/Leaflet Shape
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heart/kidney/spade
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Leaf Width
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<1/2 inch
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Leaf Venation
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palmate
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Leaf Arrangement
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opposite
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Root Type
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fibrous
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Flower Color
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inconspicuous
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lawn burrweed
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lawn burrweed
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Note: Still not
sure this is the right weed? The Turf
& Weed Identification Decision Aid may help. Check the TurfFiles glossary for definitions
of unfamiliar terms.
CULTURAL
CONTROL
Winter
annual broadleaf weeds germinate in the fall or winter and grow during any warm
weather, which may occur in the winter, but otherwise remain somewhat dormant
during the winter. They resume growth and produce seed in the spring and die as
temperatures increase in late spring and early summer. They quickly invade thin
turf areas especially where there is good soil moisture. Shade may also
encourage growth. Many have a prostrate growth habit and are not affected by
mowing. A dense, vigorous turf is the best way to reduce the encroachment of
winter annual weeds. First, select adapted turfgrass cultivars for your area
and then properly fertilize, mow, and water to encourage dense growth.
CHEMICAL
CONTROL
Lawn burrweed is controlled
postemergence in tolerant warm season turf with sulfonylurea and triazine
herbicides in fall or spring. Atrazine provides good control if applied in the
fall, but does less well if applied during the winter (December - March). Two,
three, and four way broadleaf herbicides also provide postemergence control.
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Preemergence herbicides:
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Herbicide
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Tolerant Turfs (1)
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Average
Efficacy Rating(2)
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Range of Trial Efficacy Values, %
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Number of
Trials
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Products (3)
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metolachlor
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ba, be, c, sa, z
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E
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0
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Pennant Magnum
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atrazine*
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be, c, sa, z
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G-E
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0
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AAtrex 4L
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rimsulfuron**
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be
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G-E
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0
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TranXit GTA
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Postemergence herbicides:
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Herbicide
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Tolerant Turfs (1)
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Average
Efficacy Rating(2)
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Range of Trial Efficacy Values, %
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Number of
Trials
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Products (3)
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trifloxysulfuron-sodium
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be, z
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E
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91 - 100
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7
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Monument
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metsulfuron
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be, sa, z
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E
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99 - 100
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5
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Escort**, Manor
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glyphosate
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E
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84 - 99
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2
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Glyphosate Original, Roundup, Touchdown Pro**
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rimsulfuron**
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be
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E
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98 - 100
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2
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TranXit GTA
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simazine
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be, c, sa, z
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E
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97
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1
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Princep
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2,4-D & triclopyr*
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bk, f, r
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E
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0
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Chaser
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bentazon
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ba, bc, be, bk, c, f, sa, z
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E
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0
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Basagran T/O
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clopyralid**
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ba, bc, be, bk, c, f, r, sa, z
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E
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0
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Lontrel
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dicamba
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ba, be, bk, f, r, z
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E
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0
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Banvel, Clarity, Vanquish
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imazaquin
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be, c, sa, z
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E
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0
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Image
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clopyralid & triclopyr**
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be, bk, c, f, r, z
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G
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66 - 96
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4
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Confront
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metsulfuron & sulfosulfuron
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be, sa, z
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G
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56 - 100
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3
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Certainty & Manor
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atrazine & sulfosulfuron*
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be, c, sa, z
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G
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79 - 100
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2
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AAtrex 4L & Certainty
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bispyribac sodium
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be, r
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G
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79 - 100
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2
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Velocity
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atrazine*
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be, c, sa, z
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G
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84
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1
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AAtrex 4L
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metribuzin
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be
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G
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0
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Sencor 75 Turf
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2,4-D
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be, bk, f, r, z
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G
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0
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2,4-D amine, Solution Water Soluble
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fluroxypyr & sulfosulfuron
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ba, c, sa, z
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F
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69 - 88
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2
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Certainty & Spotlight
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Footnotes:
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(1)
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Turfgrass Codes:
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ba
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bahiagrass
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bc
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bentgrass, creeping
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be
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bermudagrass
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bk
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bluegrass, Kentucky
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c
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centipedegrass
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f
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fescue, tall
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r
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ryegrass, perennial
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sa
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St. Augustinegrass
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z
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zoysiagrass
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blank
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No turfgrass in the database is
completely tolerant. Check label to see if chemical can be used at a reduced
rate or during the dormant season on your turfgrass.
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(2)
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Efficacy Ratings:
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E
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excellent control (90 to 100%)
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G
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good control (80 to 90%)
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F
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fair control (70 to 80%)
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Efficacy ratings are based on
herbicide trials performed by weed scientists at North Carolina State University between 1997 and 2007. The number of trials included in the efficacy ratings
is displayed in the next-to-last column. The higher this number, the more
confidence can be placed in the efficacy values. Trials may have involved
sequential applications of one or more chemical. Details of individual trials
(herbicide rates, dates of application, environmental conditions at time of
application, etc) can be viewed on the TurfFiles web site, through the Turf Weed Management
Decision Aid.
Efficacy ratings for chemicals
lacking trial data are from “Pest
Management Strategic Plan for Turfgrass in the Southern United States,”
summary of a workshop for turf experts from multiple universities held in Griffin, GA in October, 2004 and sponsored by the Southern Region Integrated Pest
Management Center.
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(3)
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Recommendations of specific
chemicals are based upon information on the manufacturer's label and
performance in a limited number of trials. Because environmental conditions
and methods of application may vary widely, performance of the chemical will
not always conform to the safety and pest control standards indicated by
experimental data. The order in which brand names are given is not an
indication of a recommendation or criticism.
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Recommendations for the use of
agricultural chemicals are included in this publication as a convenience to
the reader. The use of brand names and any mention or listing of commercial
products or services does not imply endorsement by North Carolina State University or discrimination against similar products or services not mentioned. Other
brand names may be labeled for use on turfgrasses. Individuals who use agricultural
chemicals are responsible for ensuring that the intended use complies with
current regulations and conforms to the product label. Be sure to obtain
current information about usage regulations and examine a current product
label before applying any chemical. For assistance, contact your county's
Cooperative Extension agent.
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© North Carolina State University. This information sheet was prepared
by Fred Yelverton, Bridget R. Lassiter, Gail G. Wilkerson, Leon Warren, Travis Gannon, Jenifer J. Reynolds, and Gregory S. Buol. Department of Crop
Science, College of Agriculture & Life Sciences, North Carolina State
University. Prepared July 15, 2008. Available on-line at
www.turffiles.ncsu.edu. This publication was made possible through a grant
provided by the Center for Turfgrass Environmental Research & Education
(CENTERE) whose purpose is to support worthwhile projects that will benefit
both the private sector and the public, and protect the environment.
KEYWORDS FOUND IN THIS ARTICLE:
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