Post-emergent dallisgrass control with solutions from Syngenta
By Lane Tredway, 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 survive through and eventually 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 (GDD) have proven to be a simple and effective tool to optimize the timing of spring applications. Based on research from the University of Tennessee, sspring applications of Fusilade® II 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 on Greencastonline.com 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 and 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 gallon 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
- An effective option for dallisgrass control in bermudagrass and zoyisagrass turf
- Apply as a broadcast (15 grams/A) or spot treatment (0.5 grams per 2 gallons water to cover 1,000 ft.2)
- A second application 4 to 6 weeks later is recommended in most cases.
- Provides broad spectrum control of many broadleaves, grasses and sedges
- Labeled for use in tall fescue and zoysiagrass turf, including residential lawns
- Apply at 3 to 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 landscapes
With Manuscript and Monument, 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, Crabgrass||Dallisgrass, Carpetgrass, Bahiagrass |
|Monument ||Dallisgrass, Sedges, Broadleaves ||Dallisgrass Poa annua, winter annuals|
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