Herbicides & Weed Control

Dr. Patrick McCullough
Associate Professor of Weed Science
The University of Georgia

Weeds are the major pests on many turfgrass sites. Weeds compete with turfgrasses for growing space, sunlight, soil moisture, and plant nutrients. Additionally, weeds detract from the natural beauty of turfgrasses due to differences in color, size, shape, and growth habit. Weeds species such as lawn burweed (Soliva pterosperma) and khakiweed (Alternanthera pungens) produce fruit with sharp-tipped spines and can cause injuries to humans. On golf courses, goosegrass (Eleusine indica) and other weeds disrupt the uniform surface of putting greens and interfere with ball roll.

Effective turfgrass weed control strategies are dependent upon correctly identifying the problem weed, its life cycle and preferred habitat. Weed species differ in their susceptibility to herbicides and other weed control strategies.

Read labels carefully for their general use on warm season grasses. Most herbicides that can be effectively used on bermudagrass are phytotoxic on paspalum.

Check the general turf use labels or warm season grass labels of all pesticides used on seashore paspalum for legality of use:

Herbicides Labeled for Seashore Paspalum

Preemergence herbicides
Summer weeds:

Echelon (prodiamine + sulfentrazone)
Freehand (pendimethalin + dimethenamid)
Pendulum, Lesco Pre-M (pendimethalin )
Specticle (indaziflam)

Winter weeds:
Balan (benefin)
Echelon (prodiamine + sulfentrazone)
Freehand (pendimethalin + dimethenamid)
Kerb (pronamide)
Pendulum, others (pendimethalin)
Prograss (ethofumesate)
Ronstar G (oxadiazon)
Specticle (indaziflam)

Postemergence herbicides
Summer weeds:

2,4-D
Banvel, others (dicamba)
Certainty (sulfosulfuron)
Defendor (florasulam)
Dismiss (sulfentrazone)
Drive (quinclorac)
Image (imazaquin)
Katana (flazasulfuron)
Lontrel (clopyralid)
Manor, others (metsulfuron)
Onetime (quinclorac + dicamba + MCPP)
Quicksilver (carfentrazone)
Sedgehammer (halosulfuron)
Solitare (sulfentrazone + quinclorac)
SpeedZone S.Augustine (2-4D, MCPP, Dicamba, Carfentrazone)
Trimec Southern, Trimec Classic (2,4-D + dicamba + MCPP)
Xonerate (amicarbazone)

Postemergence herbicides
Winter weeds:

2,4-D
Banvel, others (dicamba)
Certainty (sulfosulfuron)
Defendor (florasulam)
Image (imazaquin)
Katana (flazasulfuron)
Lontrel (clopyralid)
Onetime (quinclorac + dicamba + MCPP)
Quicksilver (carfentrazone)
Solitare (sulfentrazone + quinclorac)
Trimec Classic, Trimec Southern (2,4-D + dicamba + MCPP)
Xonerate (amicarbazone)

Herbicides for dormant turf:
Finale (glufosinate-ammonium)
Fusilade (fluazifop-butyl)
Sureguard (flumioxazin)

Herbicides safe 2-3 weeks preplant:
Ronstar WP or Ronstar G
Tower (dimethenamid)
Pennant Magnum (metolachlor)

Herbicides that are NOT SAFE
Acclaim (fenoxaprop)
Arsenal (imazapyr)
Asulox (asulam)
Celsius (thiencarbazone + iodosulfuron + dicamba)
Envoy (clethodim)
Fusilade (fluazifop)
Illoxan (diclofop)
MSMA
Monument (trifloxysulfuron)
Pylex (topramezone)
Revolver (foramsulfuron)
Ronstar WP (oxadiazon)
Roundup (glyphosate)
Segment, others (sethoxydim)
(metribuzin)
Simazine
Sureguard (flumioxazin)
Tenacity (mesotrione)
Tranxit (rimsulfuron)
Tribute Total (thiencarbazone + foramsulfuron + halosulfuron)
Turflon Ester (triclopyr)

GRass encroachment

Paspalum into bermudagrass:

  • Confront (triclopyr + clopyralid) + MSMA (0.5 and 2.0 lb.ai./A)
  • Applications at 3-4 week intervals during the Spring after full greenup
  • At least 3 repeat applications may be needed

Bermudagrass into paspalum

  • Single herbicides or combinations have been ineffective; too much damage on the paspalum
  • Have researched Prograss, Fusilade, and Envoy
plant growth regulators
  • Primo, others (trinexapac-ethyl): 0.13 ai/A on fairways; 0.125 fl oz/M or less on greens
  • Trimmit (paclobutrazol): not sensitive to rates or timing of applications; seed head suppression; minimum growth suppression
  • Legacy (trinexapac-ethyl + flurprimidol): can be applied to actively growing turf for clipping management and annual bluegrass suppression. Apply Legacy for annual bluegrass suppression in fairway height bentgrass at 8-15 fl. oz./A in early spring upon active turfgrass growth.
  • Cutless (fluprimidol): growth suppression 85 F
  • Katana (flazasulfuron): apply at 1 to 1.5 oz/acre after seashore paspalum has resumed active growth in late spring. Applications will provide seedhead suppression and growth regulation. Tank-mix trinexapac-ethyl (1EC) from 6 to 11 oz/acre to enhance growth regulation. Repeat applications at a 3 week interval as needed to maintain growth suppression.

TURFGRASS TOLERANCE TO PREEMERGENCE HERBICIDES

TURFGRASS TOLERANCE TO POSTEMERGENCE HERBICIDES

FOR MORE DETAILED INFORMATION ON WEED MANAGEMENT

TURFGRASS PEST CONTROL RECOMMENDATIONS FOR PROFESSIONALS