Aaron Griffing | 8/17/2018 3:48:53 PM
Virginia buttonweed — mat forming summer perennial broadleaf. Leaves are opposite and flowers are white with 4 lobes. Reproduces by heavy seed production. No single application provides control. Multiple applications are necessary starting in late April all the way to October.
Control options: Weed Free Zone, 2,4-D in April. Repeated metsulfuron or Cel-sius during summer. Spot treatments of glyphosate; hand remove large mats and dispose.
Torpedograss — creeping perennial grass with sharply pointed white rhizomes. Most difficult grass to manage in southern turfgrass. Repro-duces from stem fragments and rhizomes. No good control option in St. Augustinegrass or centipedegrass.
Control options: Drive, Image Crabgrass Killer and other quinclorac prod-ucts (bermudagrass, zoysiagrass) multiple apps needed; multiple applications of sethoxydim temporarily suppresses in centipede; glyphosate spot treatments (centipede and St. Aug). Totally renovate and re-sod lawn with zoysiagrass.
Dallisgrass — course textured, clumping perennial with short rhi-zomes - membranous ligule. Very competitive in drought stressed turfgrass.
Control options: Sethoxydim - repeated applications (centipede); spot treat-ments of glyphosate (bermudagrass, St. Aug). Labeled quantities of MSMA pur-
Dollarweed — creeping perennial broadleaf weed. Petiole in the center of leaf, “umbrella like”. Prefers moist soil and thin turfgrass.
Control options: MSM Turf or Repeated applications of Weed Free Zone, Weed B Gon, Atrazine, weed & feed with atrazine. Improved control by tank-mixing atrazine + Weed Free Zone or Weed B Gon (St. Aug, centipede, zoysia) - make applications from November to April.
Common bermudagrass— creeping mat-forming perennial grass that produces stolons and rhizomes. Reproduces vegetatively and by seeds. Very invasive grass that out-competes most turfgrass species. Weed in-fests St. Augustinegrass lawns mowed too short. Sometimes called “wire grass”.
Control options: Repeated applications of sethoxydim (centipede); Repeated applications of Acclaim (zoysia); spot treatments of glyphosate (St. Aug); repeated applications by a licensed applicator of Prograss + atrazine provides suppression (St. Aug). Raise mowing height to 3” (St. Aug).
Dichondra (ponyfoot)- creeping prostrate perennial that roots at the nodes. Leaves resemble a pony’s foot. Grows in thin poorly managed turf.
Control options: Weed Free Zone, Weed B Gon, and other three-way mixtures are very effective (for all southern turfgrass). Observe heat precautions with above herbicides; Atrazine (St. Aug, zoysia and centipede). Improve turf cultural practic-es such as proper fertility and correct mowing heights.
Purple and yellow nutsedge, green kyllinga — rapidly spreading grass-like perennial weeds. Purple nutsedge has deep green dagger shaped leaves and underground tubers connected by chains. Yellow nutsedge has pale green sharply tapered leaves and underground tubers that do not form chains. Green kyllinga forms weak rhizomes.
Control options: purple and yellow nutsedge - Halosulfuron (Sedgehammer and others) - safe for all southern turf. Yellow nutsedge and green kyllinga: Basagran (all southern turf).
Crabgrass and goosegrass — summer annual grasses infesting turfgrass statewide. Crabgrass germinates as early as mid-February in south Louisiana. Goosegrass often infests in compacted soils. Both species have membranous ligules. Goosegrass is more difficult to control.
Control options: preemergence herbicides in late winter (February/early March): Hi-Yield with Dimension, Green Light Crabgrass Preventer, Scotts Halts, Sta-Green Crab Ex (all southern turf). Postemergence: Image Crabgrass Killer, Drive (bermudagrass, and zoysiagrass) - not effective on goosegrass; sethoxydim (centipedegrass); Acclaim (zoysia); spot treat with glyphosate (St. Augustinegrass)
Winter broadleaves — begin germinating in late-September and are very common in thin turfgrass. Winter weeds flower in late winter and early spring are usually very heavy seed producers.
Control options: preemergence: October application of atrazine (all southern turf). Postemergence from No-vember to April: atrazine (St. Augustinegrass, centipede, zoysiagrass, dormant bermuda), Weed B Gon, Weed Free Zone, Trimec, and other three-way herbicides, MSM (metsulfuron) (all southern turf). Atrazine + Weed B Gon;
Annual bluegrass– atrazine; - Late postemergence: Weed & Feed (most turfgrass species) in April.
Common lespedeza — low growing, mat forming summer annual legume. Stems becoming woody as plant matures. Very difficult to control. Early to mid-summer applications are more effective than fall applications.
Control options: repeated apps of metsulfuron (MSM Turf, Mansion) or Celsius (St. Augustinegrass, centi-pedegrass, bermudagrass, zoysiagrass)