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RYEGRASS, ITALIAN
Ryegrass, Annual (Italian Ryegrass)
[Lolium multiflorum Lam.]
DESCRIPTION
Annual
ryegrass, also referred to as Italian ryegrass, is a bunch-type grass that can
be used as a nurse crop for quick cover or for winter overseeding of
bermudagrass on low maintenance athletic fields or golf courses. It does not
possess the quality of perennial ryegrass and is not recommended for sites
where high quality turf is desired. However, it is very inexpensive and can be
used on low profile fields such as school, park or recreation sites where
winter color is desirable. Its seedhead can be confused with that of
quackgrass. Annual ryegrass does not have rhizomes, whereas quackgrass does.
Annual ryegrass can be easily confused with tall fescue. However, tall fescue
has rough leaf blade margins on the lower 1/3 - 1/2 of the leaf whereas annual
ryegrass has smooth ones. Tall fescue has non-clasping auricles, whereas annual
ryegrass has clasping auricles. The backside of the tall fescue leaf blade is
less glossy than that of annual ryegrass.
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Characteristic
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Description
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Seedhead / Flower
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a spike, with spikelets along the main stem
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Vernation Type
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leaves rolled in the bud
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Ligule Type
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membranous; blunt, 0.04 - 0.08 inches (1 - 2 mm) long
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Growth Season / Life Cycle
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cool season turf or winter annual weed
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Auricle Type
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pointed or blunt or claw-like, clasping
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Leaf Blade Tip Shape
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sharp-pointed; bright green, upper surface dull, deeply ridged,
lower surface smooth, glossy and slightly creased, edges smooth
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Leaf Blade Width
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0.1 - 0.28 inches (3 - 7 mm) wide
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Stolon Presence
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absent
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Rhizome Presence
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absent
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Collar Type
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continuous; indistinct, not hairy
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Sheath Margin
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split with overlapping margins
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Sheath Type
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round; pinkish at base
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annual ryegrass,
clasping auricles
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annual ryegrass
leaf edge
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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
Annual
ryegrass is a common weed problem in turfgrasses on roadsides in the
southeastern United States. Maintaining a dense, vigorous turf is the first
step in effective weed control. Cultural and management practices that enhance
turfgrass growth generally reduce weed competition and encroachment. First,
select adapted turfgrass cultivars for your area and then properly fertilize,
mow, and water to encourage dense growth.
CHEMICAL
CONTROL
Annual ryegrass may be controlled
by preemergence herbicides such as pendimethalin (e.g., Pendulum) or prodiamine
(Barricade) when applied before seed germination in the fall. In dormant
bermudagrass it may be controlled also with postemergence herbicides in the
triazine and sulfonylurea families. Glyphosate (Roundup) will also control in
dormant bermudagrass. Herbicide resistance to certain postemergence herbicides
is a major concern.
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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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oryzalin
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ba, be, c, f, sa, z
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E
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86 - 95
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2
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Quali-Pro Oryzalin, Surflan A.S.
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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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clethodim**
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c
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E
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98 - 100
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2
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Envoy
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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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