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Tim MurphyExtension Weed ScientistUniversity of Georgia

Newer Weed Management Tools in Grazed Pastures

2010 Georgia Grazing SchoolPerry, GA

2Weed competition, how serious is it?Weed competition, how serious is it?

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Common Bermudagrass, Ragweed and Nitrogen

Lbs/bermuda/ac

N = 34 lbs/ac

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Fertility Examples for the Southeast Broomsedge

General indicator of low pH (<5.4), low P and low K

Affected by grazing Sericia lespedeza

Extremely tolerant of low pH, P and K

Bahiagrass and Common bermudagrassMore tolerant of low K than

hybrid bermudagrassAlso more tolerant of close

grazing

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Rule of thumb: When weeds are more than 20% of the pasture.

What is the Economic Threshold?

Woolly croton

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Do I spray or fertilize first?

Spray first.Control existing

weeds.Begin soil-test

based lime and fertilizer program.

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Grazing for Weed Control Small weeds are more palatable

Many weeds have comparable protein levels to forages

Good fencing and cattle numbers are needed

What do animals prefer?

0%

10%

20%

30%

40%

50%

60%

70%

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90%

100%

Cattle Goats Horse WT Deer

% o

f di

et Browse

Leg/BL Weeds

Grass

S. Forages 3rd Ed.

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Broomsedge is intolerant of early, heavy continuous grazing

Moulton, AL

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Examples of plants intolerant of heavy, continuous grazing

Kudzu Johnsongrass Little barley (highly

dependent upon timing)

Dogfennel (sheep) Briars (goats)

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Do we really want to eliminate all weeds from pastures?

Digestibility of select cool season weeds

0102030405060708090

% I

VD

MD

Car ger Ev prim L.Barley

TallFescue

VegBootHead

Hoveland et al., 1986

Digestibility of select warm season weeds

0

10

20

30

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60

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80

% I

VD

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Pigweed Y. foxtail Crabgrass Bermudagrass

VegBootHead

Hoveland et al., 1986

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“Weeds” in grazing situations serve multiple purposes

Can dilute toxins in tall fescue during critical timesChickweed, crabgrass,

dallisgrass, lespedeza Can extend grazing season

and improve productivityCrabgrass in tall fescue

Can improve qualityCrabgrass and

Johnsongrass

Chickweed, curly dock, shepherds purse and tall fescue mixture. Eatonton GA

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Spray or Bush Spray or Bush Hog?Hog?

About $10/acre including 1 qt/a 2,4-D

About $12 to $14/acre

More than $12/acre

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Mowing

Too late to prevent competition. No selectivity. Perennials will regrow. May prevent weed seed production. Consistency is key to effective weed

control with mowing.

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Mowing

Mowing 3 times per year for 2 years provided 80 to 90% control of ironweed and goldenrod.

19 Late summer mowing of dogfennel provided 80% control

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Herbicides and Legumes

Establish legumes after good weed control has been practiced for 1 to 2 years.

2,4-D amine is safe on white clover and lespedeza.

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Haying and Grazing Restrictions for Dairy Animals (Cattle and Goats)

Lactating Non-lactating

Herbicide Grazing Hay Grazing Hay

Metsulfuron 0 0 0 0

Cimarron Plus 0 0 0 0

Milestone 0 0 0 0

Forefront 0 7 0 7

Chaparral 0 0 (14d) 0 0 (14 d)

Grazon P+D 7 30 0 30

Remedy 14 NS* 0 7

Weedmaster 7 37 0 37

2,4-D 7 7 7 7

*Next season.

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Haying and Grazing Restrictions for Various Livestock Species

Beef Horses Goats Beef Horses Goats

Herbicide Grazing Hay

Metsulfuron 0 0 0 0 0 0

Cimarron Plus 0 0 0 0 0 0

Milestone 0 0 0 0 0 0

Forefront 0 0 0 7 7 7

Chaparral 0 0 0 0 (14) 0 (14) 0 (14)

Grazon P+D 0 0 0 30 30 30

Remedy 0 0 0 7 7 7

Weedmaster 0 0 0 37 37 37

2,4-D 0 0 0 7 7 7

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When do you spray? Winter annuals - henbit, chickweed,

buttercups, thistlesNovember through March

Summer annuals - spiny amaranth, bitter sneezeweedApril through mid-July

Perennialsgrowth stage dependent

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Spray this size Not this size

Bitter sneezeweed

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Herbicide Options1. 2,4-D2. dicamba (Vanquish, Banvel)3. 2,4-D + dicamba (WeedMaster, others)4. dicamba+ diflufenzopyr (Overdrive) 5. diuron (Direx, Diuron) 6. triclopyr (Remedy)7. imazapic (Impose,Panoramic)8. 2,4-D + triclopyr (CrossBow)9. triclopyr + clopyralid (Redeem)10.2,4-D + picloram (Grazon P+D, HiredHand,

GunSlinger)11.fluroxypyr + picloram (Surmount)12.fluroxypyr + triclopyr (PastureGard)

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Herbicide Options (cont.)13.aminopyralid (Milestone)14.aminopyralid + 2,4-D (ForeFront)15.aminopyralid + metsulfuron (Chaparral)16.Nicosulfuron + metsulfuron (Pastora)17.metsulfuron (Cimarron, MSM E.Pro, others)18.metsulfuron + chlorsulfuron (Cimarron Plus)19.metsulfuron + 2,4-D + dicamba (Cimarron MAX) 20.hexazinone (Velpar)21.sulfosulfuron (OutRider)22.pendimethalin – Prowl H2O23. tebuthiuron (Spike)24.paraquat (Gramoxone Inteon, Firestorm, Parazone)25.glyphosate (Roundup PowerMax, others)

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Newest Herbicides

PastureGard - fluroxypyr + triclopyr (Remedy)Surmount – fluroxypyr + picloramMilestone – aminopyralidForeFront – aminopyralid + 2,4-DChaparral – aminopyralid + metsulfuronOutRider – sulfosulfuronProwl H2O – pendimethalin

Pastora - nicosulfuron + metsulfuron

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PastureGard1.5 lbs./gal. triclopyr ester + 0.5 lbs./gal.

fluroxypyr esterControls numerous brush species and

broadleaf weeds.Upright blackberry, sweet gums, Sericea

lespedeza, dogfennel, gallberry, rose species, lantana

Palmetto and yucca – use 2.0% v/v solution in water

Fair control of horsenettle and tropical soda appleAlso has activity on maypop passionflower

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Reseeding Restrictions – PastureGard

Cool-season grasses and small grains - 21 days

Clover and other legumes – 30 daysOther crops – 120 days

Labeled for use on permanent grass forage systemsThis includes permanent pastures that are

overseeded with winter forages.

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Surmount

1.19 lbs./gal. picloram amine + 0.96 lbs. gal. fluroxypyr amine

Controls broadleaf weeds, horsenettle, tropical soda apple, and pricklypear cactus.

Apply 3 to 4.0 pts./acre for prickly pear cactus in fall months, control is very slow, about 2 yrs.

About 30 d residual control Excellent control of upright-growing blackberry

(3 to 4 pts./acre)

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Reseeding Restrictions – Surmount

Cool-season grasses - 21 daysClovers – 12 monthsOther legumes – 12 months

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Surmount- It’s Good - BUT!!!!!

Do notuse hay from treated areas for compost or mulchtransfer livestock to untreated areas without 7 d

cleanoutuse manure for fertilizing broadleaf cropsuse in any temporary forage system involving

broadleaf crops

USE ONLY ON PERMANENT GRASS FORAGE SYSTEMS

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Milestone

2.0 lbs./gal. aminopyralidUse rate: 4.0 to 7.0 fl. ozs./acreNumerous broadleaf weeds – thistles,

horsenettle, tropical soda apple, buttercupDo not seed legumes year of application

(additional research being conducted)Delay application until grasses have 4 to 5

leaves.

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Milestone

Non-volatileInjurious to legumes No grazing or hay restriction for any type

of livestockWeak on sida species, dogfennel,

plantains, blackberry, wild radish, other mustards.

Add 2,4-D or Remedy for weeds above.

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ForeFront0.33 lbs./gal. aminopyralid + 2.67 lbs./gal 2,4-DUse rate: 1.5 to 2.6 pts./acreNumerous broadleaf weeds – thistles,

horsenettle, buttercup, henbit, plantains, verbena

Do not seed legumes year of application (additional research being conducted)

Delay application until grasses have 4 to 5 leaves.

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ForeFront

Injurious to legumes No grazing restriction for any type of

livestock.7 day hay harvest restrictionBetter control of plantains and common

pokeweed than Milestone

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Chaparral

Bermuda, orchardgrass, tall fescue (up to 2.0 oz/a

Native grasses – wheatgrass, bluestems, grama

Apply to fully tillered or establishedSame tall fescue precautions as

metsulfuron products (2 yr establishment)

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Chaparral

Rate (oz. product/a)

Act. Ingredient 1.5 2.0* 3.0

aminopyralid 0.049 0.066 0.098

metsulfuron 0.009 0.012 0.018

*Chaparral at 2.0 oz./a = 4.0 fl. oz/a of Milestone 2SC + 0.3 oz/a Metsulfuron 60DG

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Chaparral

Non-volatileInjurious to legumes Do not seed legumes year of application

(additional research being conducted)

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Aminopyralid- It’s Good - BUT!!!!!

Do notuse hay from treated areas for compost or mulchtransfer livestock to untreated areas without

3 d cleanoutuse manure for fertilizing broadleaf cropsuse in any temporary forage system involving

broadleaf crops

USE ONLY ON PERMANENT GRASS FORAGE SYSTEMS

Grass Control Options - Bermudagrass

Dormant bermudaGlyphosate – 1.0 pt./acre (4.0 lb./gal.)Gramoxone Inteon – 1.0 to 2.0 pts./acre

Active Growth Bermuda ‘Pensacola’ bahiagrass – Cimarron, Chaparral,

ImposeSmutgrass – VelparAnnual grasses

Roundup PowerMax, after first hay cut Impose (imazapic)

Johnsongrass – OutRider, Impose Spot treat or ropewick glyphosate

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Prowl H20 - BASF

Pendimethalin Preemergence herbicide: 3.2 to 4.2 qts/acre

Needs rainfall for incorporation within 30 days of application

Labeled on dormant forage bermudagrass hay or pasture (NOT LABELED ON TALL FESCUE)

45 day hay harvest restriction 60 day grazing restriction – all livestock types See supplemental label at: http://www.cdms.net/LDat/ld6CT014.pdf

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Prowl H20 - BASF

PRE control of crabgrass, goosegrass, sandbur, Texas and fall panicum

Also controls some annual broadleaf weeds such as pigweed

Apply February to early March to dormant bermudagrass

Must be applied before annual grasses germinate (crabgrass begins germination at soil temps. of 50 to 55 F.)

Pastora – DuPont - 2010

Labeled in GA on Apr. 16, 2010 Sulfonylurea

Nicosulfuron 56.2% + Metsulfuron 15.0% Pastora controls:

Sandbur, panicum sp., foxtails, barnyardgrass, signalgrass < 2.0 in. tall Pensacola bahiagrass, before seedheads emerge in spring Vaseygrass (after hay cutting) Italian ryegrass < 6.0 in. tall Johnsongrass – 6 to 10 in. tall annual broadleaf weeds < 4.0 in. tall

Use rates: 1.0 to 1.5 oz./acre + NIS Will be used on bermudagrass only (injures tall fescue and

legumes) No grazing or haying restrictions

Effect of Pastora Applied during Greenup on Southern Crabgrass Control. 2009.

Pastora applied Apr. 15, 2009 – seedling crabgrass

(Oz/ac)

Effect of Pastora Applied mid-July on Southern Crabgrass Control. 2009.

Pastora applied July 20, 2009 – multi-tillered crabgrass

(Oz/ac)

Conclusions - Pastora

Will control Italian ryegrassCrabgrass not as sensitive as other annual

grasses (best control of crabgrass is at seedling stage)

Established bermudagrass (one growing season)

Application TimingsWinter – dormant bermudaSpring – before 2 inches of new growthSummer – within 7 days of hay cutting

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Treat at this stage

bull thistle musk thistle

Too late to spray

Thistle Control

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Thistle

Late fall or early spring application

Treat at rosette leaf stage 2,4-D ester WeedMaster Grazon P+D Chaparral ForeFront Milestone Pastora

Musk thistleMusk thistle

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Blackberry 1% Remedy or

PastureGard for spray to wet.

2-3 pints per acre for broadcast.

Metsulfuron 0.5 oz per acre

Spray at full bloom.

Repeat applications needed for complete control.

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Blackberry Control

Treatment Rate

% Control

1 year later

Grazon P+D + Remedy

1% + 0.25% 73

PastureGard 1% 87

Remedy 1% 90

Milestone 0.5% 33

June 2005 to June 2006 Faulkner County, AR

52Blackberry control with Remedy, 1 qt/ac, Fall application, 6 MAT

53Blackberry control with Cimarron Plus 0.5 ozs/ac at bloom – 5 MAT

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Dewberry

0.625 oz Cimarron Plus per acre.

Spray at full bloom.

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Dewberry

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Greenbrier Control

Treatment Rate % Control 1 yr later

PastureGard 2% 27

Remedy 2% 70

Milestone 0.5% 0

J.W. Boyd, AR

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Dogfennel Perennial – seed,

roots

Treat at 18 to 24 inch growth stage

Best – PastureGard, Remedy, Grazon P+D, Weedmaster

Good – 2,4-D, 2.0 qts./acre

Poor to Fair –Metsulfuron

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Hemp Dogbane Very tough to control. Surmount at 3 to 6 pts

per acre is the best. Remedy provides

temporary burn down.

Milky juice

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Horsenettle

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Best – Grazon P+D at 3.0 pts./acre or ForeFront at 2.6 pts/ac

Fair – WeedMaster at 4.0 pt./acre or 2,4-D at 3 pts/ac

Add a nonionic surfactant at 0.25% v/v.

Apply at mid-bloom through fruiting

Horsenettle

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Treat when small (2 to 4 inches) early May

Metsulfuron 0.25 to 0.33 oz/acre

Grazon P+D, Weedmaster, 2,4-D - 1-2 pts/acre, Cimarron Max 1 pt + 0.25 oz

Germinates all summer. Repeat applications needed.

Pigweed

Pigweed seed

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Spiny amaranth

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Identify weedIdentify weedSelect the right productSelect the right productTime the application correctlyTime the application correctlyApply accuratelyApply accuratelyFollow grazing and haying restrictionsFollow grazing and haying restrictions

Keys to Herbicide Use

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Incorporate…MowingGrazing FertilizationHerbicides

……in an integrated approach to weed management

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