2010 Georgia Grazing School:
New weed management tools for grazed pastures
Newer Weed Management
Tools in Grazed Pastures
Tim Murphy
Extension Weed Scientist
University of Georgia
2010 Grazing School for Milk Producers
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Moultrie, GA
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Common Bermudagrass, Ragweed and
Nitrogen
Fertility Examples for the Southeast
 Broomsedge
Lbs/bermuda/ac
 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
bermudagrass
N = 34 lbs/ac
 More tolerant of low K than
hybrid bermudagrass
 Also more tolerant of close
grazing
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What is the Economic Threshold?
Do I spray or fertilize first?
Rule of thumb: When weeds are more
than 20% of the pasture.
Woolly croton
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 Spray first.
 Control existing
weeds.
 Begin soil-test
based lime and
fertilizer program.
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Dr. Tim Murphy
Extension Weed Scientist
1
2010 Georgia Grazing School:
New weed management tools for grazed pastures
What do animals prefer?
Grazing for Weed Control
  Small weeds are more palatable
  Many weeds have comparable
protein levels to forages
  Good fencing and cattle numbers
are needed
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S. Forages 3rd Ed. Broomsedge is intolerant of early,
heavy continuous grazing
Examples of plants intolerant of
heavy, continuous grazing
 Kudzu
 Johnsongrass
 Little barley (highly
dependent upon
timing)
 Dogfennel (sheep)
 Briars (goats)
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Moulton, AL
Digestibility of select cool season weeds
Do we really want to eliminate all
weeds from pastures?
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Hoveland et al., 1986
Dr. Tim Murphy
Extension Weed Scientist
2
2010 Georgia Grazing School:
New weed management tools for grazed pastures
“Weeds” in grazing situations serve
multiple purposes
Digestibility of select warm season weeds
  Can dilute toxins in tall
fescue during critical times
 Chickweed, crabgrass,
dallisgrass, lespedeza
  Can extend grazing season
and improve productivity
 Crabgrass in tall fescue
  Can improve quality
 Crabgrass and
Johnsongrass
Chickweed, curly dock, shepherds
14 purse
and tall fescue mixture. Eatonton GA
Hoveland et al., 1986
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.
About $12 to $14/acre
About $10/acre including 1 qt/a 2,4-D
More than $12/acre
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Mowing
 Mowing 3 times per year for 2 years provided 80
to 90% control of ironweed and goldenrod.
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Dr. Tim Murphy
Extension Weed Scientist
3
2010 Georgia Grazing School:
New weed management tools for grazed pastures
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.
  Late summer mowing of dogfennel provided 80% control
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Haying and Grazing Restrictions for
Dairy Animals (Cattle and Goats)
Lactating
Herbicide
Haying and Grazing Restrictions for
Various Livestock Species
Non-lactating
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
Beef Horses Goats
Herbicide
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*Next season.
Beef
Grazing
Horses
Goats
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
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37
37
2,4-D
0
0
0
7
7
7
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Bitter sneezeweed
When do you spray?
  Winter annuals - henbit, chickweed,
buttercups, thistles
 November through March
  Summer annuals - spiny amaranth,
bitter sneezeweed
 April through mid-July
  Perennials
 growth stage dependent
Spray this size
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Not this size
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Dr. Tim Murphy
Extension Weed Scientist
4
2010 Georgia Grazing School:
New weed management tools for grazed pastures
Herbicide Options
1.  2,4-D
2.  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)
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 H2O
23. tebuthiuron (Spike)
24. paraquat (Gramoxone Inteon, Firestorm, Parazone)
25. glyphosate (Roundup PowerMax, others)
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Newest Herbicides
PastureGard
 1.5 lbs./gal. triclopyr ester + 0.5 lbs./gal.
fluroxypyr ester
 Controls numerous brush species and
broadleaf weeds.
 PastureGard - fluroxypyr + triclopyr (Remedy)
 Surmount – fluroxypyr + picloram
 Milestone – aminopyralid
 ForeFront – aminopyralid + 2,4-D
 Chaparral – aminopyralid + metsulfuron
 OutRider – sulfosulfuron
 Prowl H2O – pendimethalin
 Pastora - nicosulfuron + metsulfuron
 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
apple
 Also has activity on maypop passionflower 28
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Surmount
Reseeding Restrictions – PastureGard
 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)
 Cool-season grasses and small grains - 21
days
 Clover and other legumes – 30 days
 Other crops – 120 days
 Labeled for use on permanent grass
forage systems
 This includes permanent pastures that are
overseeded with winter forages.
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Dr. Tim Murphy
Extension Weed Scientist
5
2010 Georgia Grazing School:
New weed management tools for grazed pastures
Surmount- It’s Good - BUT!!!!!
Reseeding Restrictions – Surmount
 Cool-season grasses - 21 days
 Clovers – 12 months
 Other legumes – 12 months
 Do not
 use hay from treated areas for compost or
mulch
 transfer livestock to untreated areas without 7
d cleanout
 use manure for fertilizing broadleaf crops
 use in any temporary forage system involving
broadleaf crops
 USE ONLY ON PERMANENT GRASS
FORAGE SYSTEMS
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Milestone
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Milestone
 2.0 lbs./gal. aminopyralid
 Use rate: 4.0 to 7.0 fl. ozs./acre
 Numerous broadleaf weeds – thistles,
horsenettle, tropical soda apple, buttercup
 Do not seed legumes year of application
(additional research being conducted)
 Delay application until grasses have 4 to 5
leaves.
 Non-volatile
 Injurious to legumes
 No grazing or hay restriction for any type
of livestock
 Weak on sida species, dogfennel,
plantains, blackberry, wild radish, other
mustards.
 Add 2,4-D or Remedy for weeds above.
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ForeFront
ForeFront
 0.33 lbs./gal. aminopyralid + 2.67 lbs./gal
2,4-D
 Use rate: 1.5 to 2.6 pts./acre
 Numerous 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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 Injurious to legumes
 No grazing restriction for any type of
livestock.
 7 day hay harvest restriction
 Better control of plantains and common
pokeweed than Milestone
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Dr. Tim Murphy
Extension Weed Scientist
6
2010 Georgia Grazing School:
New weed management tools for grazed pastures
Chaparral
Chaparral
 Bermuda, orchardgrass, tall fescue (up to
2.0 oz/a
 Native grasses – wheatgrass, bluestems,
grama
 Apply to fully tillered or established
 Same tall fescue precautions as
metsulfuron products (2 yr establishment)
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
Aminopyralid- It’s Good - BUT!!!!!
 Non-volatile
 Injurious to legumes
 Do not seed legumes year of application
(additional research being conducted)
 Do not
 use hay from treated areas for compost or
mulch
 transfer livestock to untreated areas without
3 d cleanout
 use manure for fertilizing broadleaf crops
 use in any temporary forage system involving
broadleaf crops
 USE ONLY ON PERMANENT GRASS
FORAGE SYSTEMS
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Grass Control Options Bermudagrass
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Prowl H20 - BASF
 Dormant bermuda
 Pendimethalin
 Preemergence herbicide: 3.2 to 4.2 qts/acre
 Glyphosate – 1.0 pt./acre (4.0 lb./gal.)
 Gramoxone Inteon – 1.0 to 2.0 pts./acre
 Needs rainfall for incorporation within 30 days of
application
 Active Growth Bermuda
 ‘Pensacola’ bahiagrass – Cimarron, Chaparral,
Impose
 Smutgrass – Velpar
 Annual grasses
 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
 Roundup PowerMax, after first hay cut
 Impose (imazapic)
 Johnsongrass – OutRider, Impose
 Spot treat or ropewick glyphosate
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Dr. Tim Murphy
Extension Weed Scientist
7
2010 Georgia Grazing School:
New weed management tools for grazed pastures
Prowl H20 on the Stand Density of
Irrigated Tifton 85 Pasture. Wrens.
Prowl H20 - BASF
100  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.)
6/16/10 7/22/10 Stand Density, % 80 60 40 20 0 Control 43
Prowl H20 2.0 lb./a Prowl H20 3.0 lb./a Prowl H20 4.0 lb./a Applications made to dormant bermudagrass on 3/5/10.
Prowl H20 on Crabgrass Control in
Irrigated Tifton 85 Pastures. Wrens.
Pastora – DuPont - 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
Applications made to dormant bermudagrass on 3/5/10.
Effect of Pastora Applied during Greenup on
Southern Crabgrass Control. 2009.
Pastora – DuPont - 2010
 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
 Rotation Intervals
 Wheat, ryegrass, fescue – 4 months
 Oat, barley – 10 months
 Legumes – 12 months
(Oz/ac)
Pastora applied Apr. 15, 2009 – seedling crabgrass
Dr. Tim Murphy
Extension Weed Scientist
8
2010 Georgia Grazing School:
New weed management tools for grazed pastures
Effect of Pastora on Spring Growth of Irrigated Tifton
85 Pasture after A. Ryegrass Removal. Wrens
Effect of Pastora Applied mid-July on Southern
Crabgrass Control. 2009.
Stand Density, % 100 (Oz/ac)
5/27/10 6/16/10 8/24/10 80 60 40 20 0 Control Effect of Pastora on Goosegrass Control in
Irrigated Tifton 85 Pasture. Wrens.
100 6/16/10 Conclusions - Pastora
8/24/10  Will control Italian ryegrass
 Crabgrass not as sensitive as other annual
grasses (best control of crabgrass is at
seedling stage)
 Established bermudagrass (one growing
season)
 Application Timings
80 Control % Pastora 1.5 Pastora 1.0 oz./a oz./a + 1.0 oz./
a (20 d) Applications made on 5/6/10 and 5/27/10 for the 20 day reapplication treatment.
Control of annual ryegrass was 100% with Pastora.
Pastora applied July 20, 2009 – multi-tillered crabgrass
5/27/10 Pastora 1.0 oz./a 60 40 20 0 Control Pastora 1.0 oz./a Pastora 1.5 Pastora 1.0 oz./a oz./a + 1.0 oz./
a (20 d)  Winter – dormant bermuda
 Spring – before 2 inches of new growth
 Summer – within 7 days of hay cutting
Applications made on 5/6/10 and 5/27/10 for the 20 day reapplication treatment.
Thistle Control
Too late to spray
Thistle
Treat at this stage
bull thistle









musk thistle
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Late fall or early spring
application
Treat at rosette leaf stage
2,4-D ester
WeedMaster
Grazon P+D
Chaparral
ForeFront
Milestone
Pastora
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Dr. Tim Murphy
Extension Weed Scientist
9
2010 Georgia Grazing School:
New weed management tools for grazed pastures
Blackberry Control
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.
Rate
1% + 0.25%
1%
87
Remedy
1%
90
Milestone
0.5%
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June 2005 to June 2006 Faulkner County, AR
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Blackberry control with Remedy, 1 qt/ac, Fall application, 6 MAT57
% Control
1 year later
73
Treatment
Grazon P+D +
Remedy
PastureGard
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Blackberry control with Cimarron Plus 0.5 ozs/ac at bloom – 5 MAT
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Dewberry
Dewberry
 0.625 oz Cimarron Plus per acre.
 Spray at full bloom.
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Dr. Tim Murphy
Extension Weed Scientist
10
2010 Georgia Grazing School:
New weed management tools for grazed pastures
Dogfennel
Greenbrier Control
  Perennial – seed,
Treatment
Rate
PastureGard
2%
% Control
1 yr later
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Remedy
2%
70
Milestone
0.5%
0
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 –
J.W. Boyd, AR
Hemp Dogbane
Metsulfuron
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Horsenettle
 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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Pigweed
  Treat when small (2 to 4
inches) early May
  Metsulfuron 0.25 to 0.33
oz/acre
Horsenettle
  Grazon P+D, Weedmaster,
2,4-D - 1-2 pts/acre,
Cimarron Max 1 pt + 0.25
oz
  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
  Germinates all summer.
Repeat applications
needed.
Pigweed seed
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Dr. Tim Murphy
Extension Weed Scientist
11
2010 Georgia Grazing School:
New weed management tools for grazed pastures
Keys to Herbicide Use
Spiny amaranth
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Incorporate…
 Mowing
 Grazing
 Fertilization
 Herbicides
……in an integrated approach to weed management
????????
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Dr. Tim Murphy
Extension Weed Scientist
12