weed id & management in home...

Weed ID & Management in Turf & Lawns

Brandon W. Boughen

Potter County Agriculture & Natural Resourcesy g

Extension AgentJanuary 17, 2013y ,

Improving Lives. Improving Texas.

What is a weed?What is a weed?

• a plant that is not valued where it is growing and is usually of vigorous growth; especially : one that tends to overgrow or choke out more desirable plants.– Merriam-Webster Dictionary

What we will discussWhat we will discuss

• Grass weeds• Broadleaf weeds• Sedge weeds• Crawling or vine weeds• Crawling or vine weeds

ObjectivesObjectives

• Identify common lawn weeds• Management techniquesg• Modes of action

IDENTIFICATIONIDENTIFICATION

• Vernation.The arrangement of the leaves of the budleaf (youngest leaf) and the surrounding sheath. A folded vernation has the leaves folded in a V-shape with the margins meeting, but not overlapping. A rolled vernation has the leaves curled such that the margins are overlapping.A rolled vernation has the leaves curled such that the margins are overlapping.

• Ligule.A protruding structure from the upper surface of the leaf where the blade and the sheath are joined. This structure may be membranous, a fringe of hairs, or a membrane with hairs. The ligule can vary in both shape and size, and may also be absent.

• Auricle.A pair of appendages protruding from the side of the grass leaf at the junction of the blade and the sheath Auricles may be blunt large and claw-like and have short hairs attached or beand the sheath. Auricles may be blunt, large and claw like and have short hairs attached, or be absent.

• Sheath.The basal portion of the grass leaf between the crown and the blade. The sheath margins may be split, split with overlapping margins, or be closed.

• Collar.The region on the back side of a leaf where the leaf blade and sheath are joined. Collars may be divided by the midrib or be continuous Collar shapes vary from broad to narrow and may havebe divided by the midrib or be continuous. Collar shapes vary from broad to narrow and may have straight or slanted borders.

• Blade.The portion of the leaf, which is divided from the sheath by the collar and ligule. The length, width, type of tip, and roughness or smoothness are a few of the characteristics of various species.

• Rhizomes.An underground stem that produces a new plant. Rhizomes are present or absent, strong or weakor weak.

• Stolons.A horizontal, above ground stem that takes root at nodes and gives rise to new plants.• Seedhead The collection of flowering or seeding parts which are arranged in various ways (spike,

panicle, etc.)

DisclaimerDisclaimer

• Exclusion of product or chemical names does not imply criticism, nor does inclusion imply endorsement by Texas A&M University, Texas A&M AgriLife Extension or the author.

ANNUAL GRASSY WEEDSANNUAL GRASSY WEEDS

Annual Bluegrass P. annua LAnnual Bluegrass P. annua LVernation: folded.

Ligule: membranous, medium long, slightly pointed.

Auricle: absent.

Sheath: slightly compressed, smooth.

Collar: narrow, smooth.

Blades: short, lax, about 1/8 inch wide, the edges are ll l h h i i i "b h d"parallel to each other, terminating in a "boat-shaped"

tip.Rhizomes: none.

St lStolons: none.

Seedhead: short, open, greenish-white panicle, spikelets flattened

BarnyardgrassBarnyardgrass• Vernation: rolled (sometimeappears

nearly folded).

• Ligule: absent• Ligule: absent.

• Auricles: absent.

• Sheath: flattened, occasionally with short hairs split with overlapping edgesshort hairs, split with overlapping edges, purple tinged at base.

• Collar: narrow to broad.

• Blades: flat narrow at base thick mid• Blades: flat, narrow at base, thick mid-vein, sometimes sparsely hairy along edge, edges rough.

• Rhizomes: none.

• Stolons: none.

• Seedhead: coarse, branching panicle.

Postemergence:gFenoxaprop-ethyl (Acclaim Extra)dithiopyr (Dimension)quinclorac (Drive)quinclorac (Drive)

BermudagrassBermudagrass• Vernation: folded.

• Ligule: fringe of hairs (1-3mm).


• Sheath: flattened to round, loose, split with overlapping edges, sparsely hairy.

• Collar: narrow, continuous, may be hairy on edges.

• Blades: tapers to a point, sparsely hairy, p p p y yedges rough.

• Rhizomes: yes, stout.

• Stolons: yes, stout.y ,

• Seedhead: 3 to 5 slender spikes, joining at the top of the main stem.

Egyptian CrabgrassEgyptian Crabgrass• Vernation: rolled.

Li l h t b ith h i• Ligule: short membrane with hairs across top.


• Sheath: compressed, smooth, with some hairs near ligule.

• Collar: narrow, smooth, hairs at edges.

• Blades: flat, 7-15mm wide, sparsely hairy on edges.

• Rhizomes: short, occasional.

• Stolons: none.

• Seedhead: 2 to several thick spikes at the top of the main stem.

Fall PanicumFall Panicum• Vernation: rolled.

Li l f i f h i• Ligule: fringe of hairs.


• Sheath: slightly compressed, smooth.

• Collar: continuous, smooth.

• Blades: flat, dull above, glossy below, mid-vein prominent, 1/4 to 1/2 inch wide, sharp pointed.

• Rhizomes: none.

• Stolons: none.

• Seedhead: widely spreading open panicle, purple tinged spikelets.

Foxtail BarleyFoxtail Barley• Vernation: folded.

Li l b t ll ith j d• Ligule: membranous, tall with a jagged edge.

• Auricles: very long, membranous, twisting not clasping.

• Sheath: flattened, smooth with membranous edges.

• Collar: broad.

• Blades: flat, sparsely hairy, rough along the edges, tapering to a point.

• Rhizomes: .

• Stolons: .

• Seedhead: yellow-green, brush-like spike. Spikelets with long awns

GoosegrassGoosegrass• Vernation: folded.

• Ligule: membranous, toothed, collar-like, 0.6-1mm long, edges sometimes h h h i di id dhave short hairs, divided at center.


• Sheath: flattened, hairy at top, split with overlapping edges, edges may have hairs.

• Collar: broad, crooked fine hairs on edge.

• Blades: sparse long hairs near base on upper surface, smooth and sharply creased below, some hairs on edges, 5-10mm wide.

• Rhizomes: none.

• Stolons: none.

S dh d 2 t 6 ik t th• Seedhead: 2 to 6 narrow spikes at the top of the main stem.

Green FoxtailGreen Foxtail• Vernation: rolled.

• Ligule: dense fringe of hairs, 0.8-1mm long.


• Sheath: flattened, edges hairy, split with overlapping edges.pp g g

• Collar: narrow, hairy on edges.

• Blades: soft, flat, narrow at base, 1/4 inch wide, sharp pointed., p p

• Rhizomes: none.

• Stolons: none.

• Seedhead: soft, nodding bushy spike, green to purple, spikelets with long awns.

Large CrabgrassLarge Crabgrass• Vernation: rolled.

• Ligule: membranous (1-2mm long), toothed edge, reddish.


• Sheath: flattened, compressed, hairy.

• Collar: broad, prominent with long hairs at the edges.

• Blades: flat, sparsely hairy, 5-15mm wide, sharp pointed, rough along the d i h h iedges with hairs.

• Rhizomes: none.

• Stolons: yes.

• Seedhead: 3 to 13 narrow spikes at the top of the main stem.

RescuegrassRescuegrass• Vernation: rolled.

• Ligule: membranous, tall, rounded, often torn, hairy on the back.


• Sheath: strongly compressed, hairy to smooth in older plants, closed, forming a t b d th ttube around the stem.

• Collar: broad.

• Blades: flat, sparsely hairy, up to 1/2 i h idinch wide.

• Rhizomes: none.

• Stolons: none.

• Seedhead: open panicle, nodding, spikelets up to 1 inch in length.

SandburSandbur• Vernation: folded.

• Ligule: fringe of hairs.


• Sheath: flattened, loose, sparse hairs on the edges.

• Collar: broad, sometimes with sparse hairs on the edges.

• Blades: flat, about 1/4 inch wide, sometimes folded, tapering to a point, upper blades often enclosing burs.

• Rhizomes: none.

• Stolons: none.

• Seedhead: spike with 6 to 20 burs.

SignalgrassSignalgrass• Vernation: folded.



• Sheath: compressed, flattened, smooth.

• Collar: medium with sparse hairs at the pedges.

• Blades: very short, broad, thick, pointed.

• Rhizomes: none.

• Stolons: none.

• Seedhead: 2 to 6 slender spikes, pointing upward and alternating along the po g up a d a d a e a g a o g emain stem.

Smooth CrabgrassSmooth Crabgrass• Vernation: rolled.

• Ligule: membranous, tall, rounded.


• Sheath: compressed, smooth, generally tinged with purple.

• Collar: broad, sparsely hairy.

• Blades: sparsely hairy near the ligule, 1/4 inch wide, sharp pointed.

• Rhizomes: none.

• Stolons: none.

• Seedhead: 2 to 6 narrow spikes at the Seed ead o 6 a o sp es a etop of the main stem. Spikelets generally in two rows on each spike.

StinkgrassStinkgrass• Vernation: rolled.



• Sheath: slightly compressed.

• Collar: continuous, narrow, long hairs at , , gthe edges.

• Blades: dull above, glossy below, tapered.

• Rhizomes: none.

• Stolons: none.

• Seedhead: spreading, gray-greenSeedhead: spreading, gray green panicle, with long, compressed spikelets.

SudangrassSudangrass• Vernation: rolled.

• Ligule: membranous, tall, abrupt with a jagged edge across the top, wider than the sheaths.


• Sheath: slightly compressed, transparent along the edges.

• Collar: broad, smooth.

• Blades: flat, sharp pointed, pale green above, 1/2 inch or more wide, thick, pale green mid-vein.

• Rhizomes: none.

• Stolons: none.

• Seedhead: tall, coarse, open panicle, oval spikelets with awns.

Wild OatsWild Oats• Vernation: rolled.

• Ligule: membranous, tall, rounded, rough along the edges, sparsely hairy on h b kthe back.


• Sheath: compressed, mostly smooth, occassionally sparsely hairy.

• Collar: medium, smooth, sparsely hairy at the edges.

• Blades: flat, about 1/4 inch wide, rough to the touch, sparsely hairy near the ligule.

• Rhizomes: none.

• Stolons: none.

• Seedhead: loose, open nodding panicle, spikelets coarse, nearly one inch long

ith h t tiff h iwith short, stiff hairs.

WitchgrassWitchgrass• Vernation: rolled.



• Sheath: slightly compressed, purplish, densely hairy.

• Collar: continuous, broad, hairy.

• Blades: flat, densely hairy, 1/2 inch wide, sharp pointed.

• Rhizomes: none.

• Stolons: none.

• Seedhead: widely spreading, densely Seed ead de y sp ead g, de se yseeded panicle, sometimes half the length of the entire plant.

Yellow FoxtailYellow Foxtail• Vernation: rolled.

• Ligule: dense fringe of hairs, 1mm long.


• Sheath: sharply creased, not hairy, • flattened.

• Collar: continuous, narrow.

• Blades: long hairs on upper surface near ligule, flat, up to 12mm wide.g , , p

• Rhizomes: none.

• Stolons: none.

• Seedhead: coarse, brushy spike, yellow, spikelets with long awns.

PERENNIAL GRASSY WEEDSPERENNIAL GRASSY WEEDS

BahaigrassBahaigrass• Vernation: rolled

(sometimeappears nearly ( pp yfolded).Ligule: membranous, short, hairs on back.Auricles: absent.Sheath: flattened, sharply creased, rather glossy and usually not hairy.Collar: broad.Blades: usually sparsely hairy along edge toward base, 4-8mm wide, tapering to a tip.Rhizomes: yes, occasional.y ,Stolons: yes, stout.Seedhead: 2 or 3 slender spikes, 2 joined at top with the rest below.

BroomsedgeBroomsedge• Vernation: folded.

• Ligule: membranous, fringe of hairs.


• Sheath: very flattened, sharply creased, long hairs on edges.

• Collar: divided by mid-vein, narrow, hairy at the edges.

• Blades: 3-7mm wide, compressed near base, hairy along the edges and on upper surface near base, edges rough with long hairs.

• Rhizomes: none.

• Stolons: none.

• Seedhead: slender and narrow with 2 to 4 seeding stalks.

CarpetgrassCarpetgrass• Vernation: folded.

• Ligule: short, fringe of hairs, fused at the base.


• Sheath: compressed, flattened.

• Collar: continuous, narrow, few hairs at edges.

• Blades: short, 4-8mm wide, rounded at the tip, not hairy, edges rough near top.

• Rhizomes: none.

• Stolons: yes.

• Seedhead: 2 to 5 finger-like arms, 2 at the top of main stem with others below, spikelets a single seed.

DallisgrassDallisgrass• Vernation: rolled.

• Ligule: membranous, up to 5mm long, rounded.


• Sheath: compressed, mid-vein prominent, often long hairs near base.

• Collar: broad, continuous, sometimes hairy edges.

• Blades: flat, 7-15mm wide, sharply creased, not hairy except for possibly hairs at base, prominent mid-vein, edges rough.

• Rhizomes: occasional, very short.

• Stolons: none.

• Seedhead: 3 to 6 slender spikes, pointed upward along main stem.

JohnsongrassJohnsongrass• Vernation: rolled.

• Ligule: membranous, tall, top jagged with hairs.


• Sheath: compressed, smooth, pale green to reddish-brown.

• Collar: broad.

• Blades: flat, very long, with sparse hairs near the ligule, 1/2 inch wide, sharp pointed, mid-vein white and thick.

• Rhizomes: yes, aggressive and thick.

• Stolons: none.

• Seedhead: tall, coarse, open panicle, with oval, silky spikelets.

KnotgrassKnotgrass• Vernation: rolled.

• Ligule: membranous, tall, rounded.


• Sheath: compressed, smooth, hairy edges.

• Collar: broad with long hairs on edges.

• Blades: flat or folded, hairy near ligule, sparse hairs along edge.

• Rhizomes: yes, strong.

• Stolons: yes.

• Seedhead: 2 spikes at the top of the• Seedhead: 2 spikes at the top of the main stem.

LovegrassLovegrass• Vernation: rolled.



• Sheath: slightly compressed.

• Collar: continuous, medium, hairy at the , , yedges.

• Blades: narrow, flat, tapered, rough above, smooth below.

• Rhizomes: none.

• Stolons: none.

• Seedhead: delicate, open panicle, hairySeedhead: delicate, open panicle, hairy where branches join the main stem.

NimblewillNimblewill• Vernation: rolled.

Li l b h t j d• Ligule: membranous, short, jagged.


• Sheath: compressed, flattened, smooth, split, prominent white membrane along edge.

• Collar: broad, hairy on edges.

• Blades: short, narrow, flat, pointed, 2-2.5mm wide.

• Rhizomes: yes.

• Stolons: yes, fine.

• Seedhead: loose, spike-like panicle, spikelets have long awns.

OrchardgrassOrchardgrass• Vernation: folded.

Li l b t ll• Ligule: membranous, very tall, sometimes jagged across top.


• Sheath: strongly compressed, flattened, green above-white below, mostly split part way.

• Collar: divided, broad, distinct.

• Blades: V-shaped, long and pointed, deep furrow over mid-vein, edges rough.

• Rhizomes: none.

• Stolons: none.

• Seedhead: panicle, stiff branches terminating with fan-shaped spikelets.

QuackgrassQuackgrass• Vernation: rolled.

Li l b h t• Ligule: membranous, very short.

• Auricles: claw-like, slender, clasping the stem.

• Sheath: not compressed, lower sheaths hairy, upper sheaths smooth.

• Collar: broad, continuous, may be divided, sometimes hairy.

• Blades: 5-12mm wide, flat, rough uper surface, smooth below, pointed, edges sparsely hairy.

Rhi t• Rhizomes: yes, strong.

• Stolons: none.

• Seedhead: spike with spikelets facing th i tthe main stem.

Smooth BromegrassSmooth Bromegrass• Vernation: rolled.

Li l b h t• Ligule: membranous, short.


• Sheath: not compressed, closed nearly to the top.

• Collar: narrow, continuous.

• Blades: 1/4 inch wide, smooth, often constricted to form an "M" or "W".

• Rhizomes: yes, strong.

• Stolons: none.

• Seedhead: erect panicle, with branches in a circular pattern around the stem.

SmutgrassSmutgrass• Vernation: rolled.

Li l f i f h i• Ligule: fringe of hairs.


• Sheath: smooth, round.

• Collar: divided into two parts by the mid-vein.

• Blades: flat, less than 1/4 inch wide, tapering to a sharp point.

• Rhizomes: none.

• Stolons: none.

• Seedhead: long, narrow, spike-like panicle, often black with smutty fungus.

Wild BarleyWild Barley• Vernation: rolled.

Li l b h t• Ligule: membranous, short.


• Sheath: compressed.

• Collar: divide by the mid-vein.

• Blades: narrow, long, tapering to a point, rough to the touch.

• Rhizomes: none.

• Stolons: none.

• Seedhead: yellow-green to purple, nodding, bushy spike, 11/2 tp 3 inches long, spikelets with long, barbed awns, rough to the touch.

WindmillgrassWindmillgrass• Vernation: folded.

• Ligule: membranous, tall, hairs at the top.p


• Sheath: compressed, very flat, with a sparsely hairy and prominent mid-vein, spa se y a y a d p o e d e ,edges are transparent.

• Collar: broad, with long hairs.

• Blades: narrow, short, 1/8 inch wide,Blades: narrow, short, 1/8 inch wide, folded, crowded at the base, sparse hairs on the prominent mid-vein.

• Rhizomes: none.

• Stolons: none.

• Seedhead: long slender spikes spreading away from the main stem in a circular pattern, 1 to 3 spaced groups, p , p g p ,spikelets with long awns.

BROADLEAF WEEDSBROADLEAF WEEDS

Black MedicBlack Medic

Common ChickweedCommon Chickweed

White CloverWhite Clover

• Use a surfactant on Black Medic, Common Chickweed & White Clover

DandelionDandelion

Curly DockCurly Dock

Dollarweed (Pennywort)Dollarweed (Pennywort)

Field BindweedField Bindweed

• Bindweed Mite• Spray when flowering, ofteny g

Whitestem FilareeWhitestem Filaree

HenbitHenbit

Knotweed, ProstrateKnotweed, Prostrate

Prickly LettucePrickly Lettuce

Broadleaf PlantainBroadleaf Plantain

PurslanePurslane

Creeping SpurgeCreeping Spurge

Spotted SpurgeSpotted Spurge

• Use surfactant

Bull ThistleBull Thistle

Canada ThistleCanada Thistle

Musk ThistleMusk Thistle

• Tordon 22K• Spray early when in rosette y y

Creeping WoodsorrelCreeping Woodsorrel

Yarrow, CommonYarrow, Common

Shephrd’s PurseShephrd s Purse

Redstem FilareeRedstem Filaree

HorseweedHorseweed

Silverleaf NightshadeSilverleaf Nightshade

Redroot PigweedRedroot Pigweed

Russian ThistleRussian Thistle

DodderDodder

• Burn• Mechanical

Yellow NutsedgeYellow Nutsedge

MODES OF ACTIONMODES OF ACTION

• Mode of action refers to the effect a herbicide has on a plant

• Preemergence- kill weeds shortly after they germinate

• Postemergence- kill weeds that are already growing and visibleare already growing and visible

Eight modes of actionEight modes of action• Growth regulator

Ph t th i i hibit• Photosynthesis inhibitors• Pigment inhibitors• Seedling growth inhibitors• Cell membrane disrupters andCell membrane disrupters and

organic arsenicals• Lipid synthesis inhibitors• Lipid synthesis inhibitors• Amino acid synthesis inhibitors• Other amino acid synthesis

inhibitors

Growth regulatorsGrowth regulators

• Widely used to control broadleaf weedsweeds

• Upset the normal hormonalhormonal balance of the plantp

Photosynthesis inhibitorsPhotosynthesis inhibitors

• Critical to cotton, corn and rice production inproduction in Texas

Pigment inhibitorsPigment inhibitors

• Bleaching herbicidesD t• Destroys carotenoids

Seedling growth inhibitorsSeedling growth inhibitors

• Root inhibitors: interrupt cell division

• Shoot inhibitors: disrupt cell growthdivision

• Works well on small-seeded

growth• If over applied,

may becomesmall-seeded broadleaf and grass seed

may become ineffective

g

Cell membrane disruptersCell membrane disrupters

• Destroys cell membranes and causes rapidcauses rapid dessication of plantplant

• MSMA is OK, but only for Cotton, y ,golf course, sod farm, right-of-way

Lipid synthesis inhibitorsLipid synthesis inhibitors

• Act only on annual and perennialperennial grasses, not broadleaf plantsbroadleaf plants

• If grass weeds are stressed the herbicides will be less effective

Amino Acid synthesis I hibitInhibitors

• Controls both broadleaf and grasses has soilgrasses, has soil and foliar activity

• Essentially• Essentially nontoxic to mammals

Other herbicidesOther herbicides

• These herbicides are nonselectiveTh h bi id• These herbicides have not yet been classified tobeen classified to a family

[email protected]

Good websitesGood websites• HRAC Global

– http://www.hracglobal.com/Home/tabid/121/Default.p gaspx

• WSSA– http://www.wssa.net/index.htm

• WEED ALERT– http://www.weedalert.com/

• TWIG– http://twig.tamu.edu/weedid.htm

• PAN– http://www.pesticideinfo.org/

ResourcesResources• Texas AgriLife Extension Service

U i it f C lif i IPM O li• University of California IPM Online• University of Illinois Turfgrass Program• Virginia Tech Weed Identification GuideVirginia Tech Weed Identification Guide• Colorado State University, Denver County

Extension Master Gardeners• University of Tennessee Cooperative Extension• Herbicides, how they work and the symptoms

they cause; AgriLife Extension E 529they cause; AgriLife Extension – E-529• www.extension.org• EPAEPA

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