Post-emergent dallisgrass control in warm- and cool-season turfgrasses

By Lane Tredway, Ph.D., technical services manager for Syngenta

Dallisgrass is possibly the most difficult weed to control in the transition zone. This aggressively growing, perennial grass has an impressive ability to recover from herbicide applications thanks to its robust rhizomes. Dallisgrass is most sensitive to post-emergent herbicides in the spring to early summer and again in the late summer to early fall, so careful timing is essential to getting the best performance.

Growing Degree Days (GDDs) have proven to be a simple, effective tool to optimize the timing of spring applications. Based on research from the University of Tennessee, spring applications of Fusilade® II herbicide were most effective beginning between 270 and 360 GDD50 with accumulation beginning January 1. This GDD-based timing has also performed well for other chemistries targeting dallisgrass. Visit the GGD tool from Syngenta to see the current GDD accumulation in your area, or to sign up for email alerts when GDD thresholds are met.

Syngenta offers three solutions for dallisgrass management:

    • Labeled for use in bermudagrass, zoyisagrass turf and in St. Augustinegrass sod
    • Apply as a spot treatment using 0.96 fl. oz. of Manuscript and 0.64 fl. oz. Adigor™ surfactant in 1 gal. of water to treat 1,000 ft.2
      • Make a second application 14 to 21 days later and treat no more than 10,000 ft.2 per acre per year
    • Also provides effective control of crabgrasses and several other grassy weeds

  • Monument® 75WG herbicide
    • An effective option for dallisgrass control in bermudagrass and zoyisagrass turf
    • Apply as a broadcast or spot treatment at 0.53 oz. or 15 g/A  as directed by the label
      • A second application four to six weeks later is recommended in most cases
    • Provides broad-spectrum control of many broadleaves, grasses and sedges
  • Fusilade II herbicide
    • Labeled for use in tall fescue and zoysiagrass turf, including residential lawns
    • Apply at 3-6 fl. oz./A as specified on the product label
    • Make a repeat application 30 days later
      • Avoid spray overlaps or application to turfgrasses under stress, which may induce unacceptable turf injury
    • Applications will also suppress or control bermudagrass contamination in tall fescue or zoysiagrass
With Manuscript and Monument 75WG, Syngenta now offers multiple chemistries for dallisgrass control in bermudagrass and zoysiagrass, which can be assembled into an effective season-long approach depending on other weed pressures present (see table below).

Product  Spring-Early Summer  Late Summer-Fall
Manuscript            Dallisgrass, crabgrassDallisgrass, carpetgrass, bahiagrass  
Monument 75WG   Dallisgrass, sedges, broadleaves    Dallisgrass, Poa annua, winter annuals
Syngenta hereby disclaims any liability for Third Party websites referenced herein.

© 2024 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties and/or may have state-specific use requirements. Please check with your local extension service to ensure registration and proper use. Adigor™, Fusilade®, Manuscript®, Monument® and the Syngenta logo are trademarks of a Syngenta Group Company.

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