1 Tim Murphy Extension Weed Scientist University of Georgia Weed Management in Grazed Pastures 2009 Georgia Grazing School UGA-Athens

2 Weed competition, how serious is it?

3 Common Bermudagrass, Ragweed and Nitrogen Lbs/bermuda/ac N = 34 lbs/ac

4 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 bermudagrass  More tolerant of low K than hybrid bermudagrass  Also more tolerant of close grazing

5 Rule of thumb: When weeds are more than 20% of the pasture. What is the Economic Threshold? Woolly croton

6 Do I spray or fertilize first?  Spray first.  Control existing weeds.  Begin soil-test based lime and fertilizer program.

7 Grazing for Weed Control Small weeds are more palatable Many weeds have comparable protein levels to forages Good fencing and cattle numbers are needed

8 Effect of Grazing on Weed Control  Grazing is SELECTIVE defoliation  Unlike mowing this may allow greater pressure to be placed on a single forage species  Shift competitive advantage toward favorable species  Can alter selectivity with animal species, stocking rate and timing

What do animals prefer? S. Forages 3 rd Ed.

10 Broomsedge is intolerant of early, heavy continuous grazing Moulton, AL

11 Examples of plants intolerant of heavy, continuous grazing  Kudzu  Johnsongrass  Little barley (highly dependent upon timing)  Dogfennel (sheep)  Briars (goats)

12 Do we really want to eliminate all weeds from pastures?

Digestibility of select cool season weeds Hoveland et al., 1986

Digestibility of select warm season weeds Hoveland et al., 1986

15 “Weeds” in grazing situations serve multiple purposes  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 purse and tall fescue mixture. Eatonton GA

16 Spray or Bush Hog? About $10/acre including 1 qt/a 2,4-D About $12 to $14/acre More than $12/acre

17 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.

18

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

20  Late summer mowing of dogfennel provided 80% control

21 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.

22 Haying and Grazing Restrictions for Dairy Animals (Cattle and Goats) LactatingNon-lactating HerbicideGrazingHayGrazingHay Metsulfuron0000 Cimarron Plus0000 Milestone0000 Forefront0707 Chaparral00 (14d)0 Grazon P+D7300 Remedy14NS*07 Weedmaster7370 2,4-D7777 *Next season.

23 Haying and Grazing Restrictions for Various Livestock Species BeefHorsesGoatsBeefHorsesGoats HerbicideGrazingHay Metsulfuron Cimarron Plus Milestone Forefront Chaparral0000 (14) Grazon P+D00030 Remedy Weedmaster ,4-D000777

24 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

25 Spray this size Not this size Bitter sneezeweed

26 Herbicide Options  2,4-D  dicamba (Vanquish, Banvel)  2,4-D + dicamba (WeedMaster, others)  dicamba+ diflufenzopyr (Overdrive)  triclopyr (Remedy)  imazapic (Impose,Panoramic)  2,4-D + triclopyr (CrossBow)  triclopyr + clopyralid (Redeem)  2,4-D + picloram (Grazon P+D, HiredHand, GunSlinger)  fluroxypyr + picloram (Surmount)  fluroxypyr + triclopyr (PastureGard)

27 Herbicide Options (cont.)  aminopyralid (Milestone)  aminopyralid + 2,4-D (ForeFront)  aminopyralid + metsulfuron (Chaparral)  diuron (Direx, Diuron)  metsulfuron (Cimarron, MSM E.Pro, others)  metsulfuron + chlorsulfuron (Cimarron Plus)  metsulfuron + 2,4-D + dicamba (Cimarron MAX)  hexazinone (Velpar)  sulfosulfuron (OutRider)  tebuthiuron (Spike)  paraquat (Gramoxone Inteon, Firestorm, Parazone)  glyphosate (Roundup PowerMax, others)

28 Newest Herbicides  PastureGard - fluroxypyr + triclopyr (Remedy)  Surmount – fluroxypyr + picloram  Milestone – aminopyralid  ForeFront – aminopyralid + 2,4-D  Chaparral – aminopyralid + metsulfuron  OutRider - sulfosulfuron

29 PastureGard  1.5 lbs./gal. triclopyr ester lbs./gal. fluroxypyr ester  Controls 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 apple  Also has activity on maypop passionflower

30 Reseeding Restrictions – PastureGard  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.

31 Surmount  1.19 lbs./gal. picloram amine 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)

32 Reseeding Restrictions – Surmount  Cool-season grasses - 21 days  Clovers – 12 months  Other legumes – 12 months

33 Surmount- It’s Good - BUT!!!!!  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

34 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.

35 Milestone  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.

36 ForeFront  0.33 lbs./gal. aminopyralid 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.

37 ForeFront  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

38 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, except no 24 mo. establishment restriction.

39 Chaparral Rate (oz. product/a) Act. Ingredient1.52.0*3.0 aminopyralid metsulfuron *Chaparral at 2.0 oz./a = 4.0 fl. oz/a of Milestone 2SC oz/a Metsulfuron 60DG

40 Chaparral  Non-volatile  Injurious to legumes  Do not seed legumes year of application (additional research being conducted)

41 Aminopyralid- It’s Good - BUT!!!!!  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

42 Potential New Registrations  Pendimethalin – October, 2009?  Prowl H 2 0  Complete with ongoing trials  GA, AR, NC, SC, MS, TN, OK   Pastora – early summer 2010?  DuPont  Sandbur, other annual grasses, annual broadleaf weeds

43 Treat at this stage bull thistlemusk thistle Too late to spray Thistle Control

44 Thistle  Late fall or early spring application  Treat at rosette leaf stage  2,4-D ester qt./acre  WeedMaster pt./acre  Grazon P+D pt./acre  CrossBow pt./acre Musk thistle

45 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.

46 Blackberry Control TreatmentRate % Control 1 year later Grazon P+D + Remedy 1% %73 PastureGard1%87 Remedy1%90 Milestone0.5%33 June 2005 to June 2006 Faulkner County, AR

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

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

49 Dewberry  oz Cimarron Plus per acre.  Spray at full bloom.

50 Dewberry

51 Greenbrier Control TreatmentRate% Control 1 yr later PastureGard2%27 Remedy2%70 Milestone0.5%0 J.W. Boyd, AR

52 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

53 Hemp Dogbane  Very tough to control.  Surmount at 3 to 6 pts per acre is the best.  Remedy provides temporary burn down. Milky juice

54 Horsenettle

55  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

56  Treat when small (2 to 4 inches) early May  Metsulfuron 0.25 to 0.33 oz/acre  Grazon P+D, Weedmaster, 2,4-D pts/acre, Cimarron Max 1 pt oz  Germinates all summer. Repeat applications needed. Pigweed Pigweed seed

57 Spiny amaranth

58  Identify weed  Select the right product  Time the application correctly  Apply accurately  Follow grazing and haying restrictions Keys to Herbicide Use

59 Incorporate…  Mowing  Grazing  Fertilization  Herbicides ……in an integrated approach to weed management

60 ????????