P-T Weeds

Control of Common Weeds

Weeds are indexed alphabetically.  Select the section of interest.



Poa trivialis in Bentgrass
Velocity at 2.6 oz/acre twice 3 weeks apart or Certainty at 0.25 oz/a applied 3 weeks apart.  Expect short-term phytotoxicity. Poa trivialis is suppressed in perennial ryegrass with fenoxaprop (Acclaim Extra) every 2 to 3 weeks from April to September or ethofumesate (Prograss) in Oct. and Nov. Lower rates must be used in bentgrass, thus, poorer control often results. Spot treat with glyphosate (Roundup Pro, others) in late summer just prior to overseeding.

Purple Nutsedge (Cyperus rotundus)
Monument at 0.56 oz/acre or Certainty at 1.25 oz/acre in bermudagrass and zoysiagrass. Make a repeat application six to eight weeks after the first. Two applications of Manage 75 DF at 1.33 oz/acre rate four to six weeks apart provide suppression for most of the growing season. The spot treatment rate for Manage is 0.9 gram per gallon. Manage is not labeled for golf greens. Manage is safe on all turfgrasses. Image 70 DG (imazaquin) is an effective herbicide for suppressing sedges in turfgrass. It is approved for use on bermudagrass, zoysiagrass, St. Augustinegrass and centipedegrass. The recommended rate is 0.26 oz of product per 1,000 sq ft. This translates to 11.4 oz/acre. The active ingredient rate is 0.5 lb/acre. A repeat application will be needed for full-season suppression. Make the repeat application in four to six weeks or when regrowth appears. A tank mix of 0.5 lb/acre of Image + 2.0 lb/acre MSMA has given better suppression than either product alone. Do not use the MSMA tank mix on St. Augustinegrass or centipedegrass. Image + MSMA will cause significantly more injury to zoysiagrass than bermudagrass. The coarse-leaved japonica type zoysiagrasses tend to be more herbicide tolerant than the fine-leaved matrella types.

Sandbur (Sandspur) (Cenchrus sp.)
Preemergence control in early spring with split applications 60 days apart of PRE herbicides such as Barricade, Dimension, Pendimethalin, Ronstar, or Surflan.  Postemergence control in bermuda/zoysia - MSMA (1 lb ai/a).  Repeat in 10 days.  In centipedegrass: Vantage 1L @ 2 pts/a. Repeat in 21 days.  In fescue/zoysia - repeat Acclaim Extra (0.57 EC) at 1½ pts/A or Fusilade T&O (2EC) at 5 to 6 oz/a on 30 day intervals.  Use only on fescue >4 weeks old, start in spring, need good soil moisture, discontinue during summer stress.

Smutgrass (Sporobolus indicus)
Selective control has been very elusive.  Best control in warm-season grasses are repeat summer atrazine or simazine applications 10 days apart. Add a crop oil concentrate.   However, expect temporary turfgrass damage with this.  Non-selective control is spot spraying or rope wicking glyphosate (Roundup Pro).  If rope wicking, treat in two directions.

Spurges (Chamaesyce sp.)
Summer annuals species include spotted, prostrate, garden, and round-leaf spurges. These often act as indicator plants for high nematode containing soils. Manor or Blade 60DF at 0.25 oz/a provides best control.  Two and three-way mixes of 2,4-D, dicamba, and MCPP also work.  Repeat applications of the mixes may be necessary as plants mature.

Tall Fescue Clumps (Festuca arundinacea)
Postemergence control in Ky. bluegrass, fine fescue, zoysiagrass, or bermudagrass - Corsair 75DF at 4 to 5 oz/a or as a spot treatment at 2½ grams/2 gal water.  In bermudagrass and zoysiagrass, Revolver 0.19L at 26 oz/a, TranXit at 2 to 4 oz/acre, or Monument at 0.56 oz/a. In dormant bermudagrass, spot treat with Roundup Pro 4L at 2 oz/gal water, avoid desirable green plants.  Repeat in 60 days.

Thin or Bull Paspalum (Paspalum setaceum)
Repeat applications of MSMA or DSMA are required every 7 days until complete control is achieved. Add Dismiss at 8 oz/acre for increased control.

Torpedograss (Panicum repens)
Nonselective control is with at least 3 applications of glyphosate (Roundup Pro) each spaced 3 weeks apart.  Other nonselective control involves fumigating with methyl bromide and replanting.  Selective control (or suppression) available with quinclorac (Drive) and trifloxysulfuron (Monument).  These should be applied 2 or 3 times spaced three to four weeks apart.  Expect some minor temporary turfgrass discoloration.

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