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CUDWEED
Cudweed
[Gnaphalium, Pseudognaphalium, & Gamochaeta spp.]
DESCRIPTION
The
cudweeds are comprised of many different species that are similar in growth
habits and control measures. In general, the cudweeds have basal rosettes and
the leaves and seedheads are covered in distinct fine, white "wooly"
fibers. Some cudweeds only have this hair on the undersides of the leaves, and
other cudweeds have this hair on all surfaces. Cudweeds overwinter as small
basal rosettes, but in the spring usually grow an upright stem.
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Characteristic
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Description
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Growth Season
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summer annual or winter annual or biennial weed
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Growth Habit
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upright; rosette
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Leaflet Number
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one
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Leaf Margin
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smooth
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Leaf Hairs
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upper/lower surface
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Leaf/Leaflet Shape
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oval/egg-shaped/elliptical
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Leaf Width
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1/2 - 2 inches
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Leaf Venation
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pinnate; leaf venation is hard to see, but leaves usually look
like they have been folded or creased
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Leaf Arrangement
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whorled or basal rosette
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Root Type
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taproot
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Flower Color
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flower is tanish white, and produces a white fiber
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cudweed
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cudweed
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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
Proper turf
management is important for biennial broadleaf weed control. Maintain a dense,
actively growing turf through proper mowing, fertilizing, and watering
practices. Mow at the proper height for your selected adapted turfgrass. Coring
and traffic control reduce compaction and encourage desirable turfgrass
competition. It is best to control this biennial broadleaf weed in spring or
fall, if actively growing at these times.
CHEMICAL
CONTROL
Cudweed species are biennial
plants but are relatively easy to control. Two, three, and four way broadleaf
herbicides control postemergence as do metribuzin (Sencor) and repeat
applications of metsulfuron (Manor, Blade, etc.). Apply in the spring while in
rosette stage and before seed stalk formation.
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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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atrazine*
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be, c, sa, z
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E
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0
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AAtrex 4L
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isoxaben
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ba, bc, be, bk, c, f, r, sa, z
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F
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0
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Gallery 75
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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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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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2,4-D
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be, bk, f, r, z
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G-E
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0
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2,4-D amine, Solution Water Soluble
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2,4-D & triclopyr*
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bk, f, r
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G-E
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0
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Chaser
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clopyralid & triclopyr**
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be, bk, c, f, r, z
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G-E
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0
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Confront
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atrazine*
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be, c, sa, z
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G
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0
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AAtrex 4L
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glyphosate
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G
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0
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Glyphosate Original, Roundup, Touchdown Pro**
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MSMA***
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be, r
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F-G
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0
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MSMA (various brands)
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imazaquin
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be, c, sa, z
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F
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0
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Image
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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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